U.S. patent application number 12/882898 was filed with the patent office on 2011-06-09 for silicon wafer cleaning agent.
This patent application is currently assigned to Central Glass Company, Limited. Invention is credited to Yoshinori AKAMATSU, Soichi KUMON, Hidehisa NANAI, Takashi SAIO, Masanori SAITO.
Application Number | 20110132397 12/882898 |
Document ID | / |
Family ID | 43405557 |
Filed Date | 2011-06-09 |
United States Patent
Application |
20110132397 |
Kind Code |
A1 |
KUMON; Soichi ; et
al. |
June 9, 2011 |
Silicon Wafer Cleaning Agent
Abstract
A silicon wafer cleaning agent includes at least a water-based
cleaning liquid, and a water-repellent cleaning liquid for
providing water-repellent to an uneven pattern at least at recessed
portions during a cleaning process. The water-repellent cleaning
liquid is a liquid composed of a water-repellent compound
containing a reactive moiety which is chemically bondable to Si in
the silicon wafer, and a hydrophobic group, or is a liquid wherein
0.1 mass % or more of the water-repellent compound relative to the
total quantity of 100 mass % of the water-repellent cleaning liquid
and an organic solvent are mixed and contained therein. A cleaning
process wherein a pattern collapse is easily induced can be
improved by using the cleaning agent.
Inventors: |
KUMON; Soichi;
(Matsusaka-shi, JP) ; SAITO; Masanori;
(Matsusaka-shi, JP) ; SAIO; Takashi; (Suzuka-shi,
JP) ; NANAI; Hidehisa; (Tokyo, JP) ; AKAMATSU;
Yoshinori; (Matsusaka-shi, JP) |
Assignee: |
Central Glass Company,
Limited
Ube-shi
JP
|
Family ID: |
43405557 |
Appl. No.: |
12/882898 |
Filed: |
September 15, 2010 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
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PCT/JP2010/050390 |
Jan 15, 2010 |
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12882898 |
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Current U.S.
Class: |
134/6 ;
134/115R |
Current CPC
Class: |
C11D 7/30 20130101; C11D
11/0047 20130101; C11D 11/007 20130101; C11D 7/3209 20130101; C11D
11/0064 20130101; H01L 21/02052 20130101 |
Class at
Publication: |
134/6 ;
134/115.R |
International
Class: |
B08B 3/00 20060101
B08B003/00 |
Foreign Application Data
Date |
Code |
Application Number |
Jan 21, 2009 |
JP |
2009-011128 |
Jan 21, 2009 |
JP |
2009-011129 |
Dec 25, 2009 |
JP |
2009-293916 |
Dec 25, 2009 |
JP |
2009-293953 |
Claims
1-10. (canceled)
11. A cleaning agent for a silicon wafer having a finely uneven
pattern at its surface which cleaning agent comprises two or more
cleaning liquid and used while substituting a cleaning liquid
retained in a recessed portion of the uneven pattern with another
cleaning liquid, comprising: a water-based cleaning liquid; and a
water-repellent, cleaning liquid for providing at least the
recessed portion of the uneven pattern with water repellency during
a cleaning process, the water-repellent cleaning liquid is one of:
a liquid comprising a water-repellent compound having a reactive
moiety chemically bondable to Si in the silicon wafer, and a
hydrophobic group; and a liquid in which the water-repellent
compound of 0.1-50 mass % relative to the total quantity of 100
mass % of the water-repellent cleaning liquid and an organic
solvent are mixed and contained, wherein a capillary force on the
assumption that water is retained in the recessed portion formed at
the surface of the silicon wafer which recessed portion is provided
with water repellency by the water-repellent cleaning liquid is not
higher than 2.1 MN/m.sup.2.
12. A cleaning agent for a silicon wafer, as claimed in claim 11,
wherein the water-repellent cleaning liquid is the liquid in which
the water-repellent compound and the organic solvent are mixed and
contained, wherein the water-repellent cleaning compound is mixed
and contained in the water-repellent cleaning liquid in an amount
of 0.1-50 mass % relative to the total quantity of 100 mass % of
the water-repellent cleaning liquid, wherein the organic solvent
containing a nitrogen-containing solvent, and wherein an element of
the nitrogen-containing solvent to be bonded to nitrogen is
carbon.
13. A cleaning agent for a silicon wafer, as claimed in claim 12,
wherein the nitrogen-containing solvent is at least one selected
from the group consisting of tertiary amide, tertiary amine,
1-alkyl-2-pyrrolidone and compounds having pyridine ring.
14. A cleaning agent for a silicon wafer, as claimed in claim 11,
wherein the water-repellent compound in the water-repellent
cleaning liquid which compound has the reactive moiety chemically
bondable to Si in the silicon wafer and the hydrophobic group
comprises at least one selected from the group consisting of the
following general formulas [1], 121 and [3].
(R.sup.1).sub.aSi(CH.sub.3).sub.bH.sub.cX.sub.4-a-b-c [1]
[R.sup.2Si(CH.sub.3).sub.2-dH.sub.d].sub.eNH.sub.3-e [2]
R.sup.3Si(CH.sub.3).sub.2Y [3] where: R.sup.1, R.sup.2 and R.sup.3
is a monovalent organic group having hydrocarbon group with a
carbon number of 1 to 18 or a monovalent Organic group having
perfluoroalkyl chain with a carbon number of 1 to 8; X represents
chloro group, isocyanate group, alkoxy group, acetoxy group,
trifluoroacetoxy group, --OC(CH.sub.3).dbd.CHCOCH.sub.3,
alkylsulfonate group, perfluoroalkylsulfonate group, or nitrile
group; Y represents a monovalent organic group whose element to be
bonded to Si is nitrogen; a is an integer of from 1 to 3; b and c
are integers of from 0 to 2; the total of a, b and c is from 1 to
3; d is an integer of from 0 to 2; and e is an integer of from 1 to
3.
15. A cleaning agent for a silicon wafer, as claimed in claim 11,
wherein the organic solvent mixed with the water-repellent compound
is an aprotic solvent.
16. A cleaning agent for a silicon wafer, as claimed in claim 11,
wherein the organic solvent mixed with the water-repellent compound
is a halogen-containing uninflammable solvent.
17. A cleaning agent for a silicon wafer, as claimed in claim 11,
wherein the organic solvent mixed with the water-repellent compound
is a derivative of polyhydric alcohol having no hydroxyl group.
18. A water-repellent cleaning liquid used during a cleaning
process for a silicon wafer having at its surface a finely uneven
pattern, for providing the silicon wafer with water repellency at
least on a recessed portion of the uneven pattern during the
cleaning process, the water-repellent cleaning liquid being one of:
a liquid comprising a water-repellent compound having a reactive
moiety chemically bondable to Si in the silicon wafer and a
hydrophobic group; and a liquid in which 0.1-50 mass % of the
water-repellent compound relative to the total quantity of 100 mass
% of the water-repellent cleaning liquid and an organic solvent are
mixed and contained.
19. A water-repellent cleaning liquid as claimed in claim 18,
wherein the water-repellent cleaning liquid is the liquid in which
the water-repellent compound and the organic solvent are mixed and
contained; wherein the water-repellent compound is mixed and
contained in the water-repellent cleaning liquid in an amount of
0.1-50 mass % relative to the total quantity of 100 mass % of the
water-repellent cleaning liquid; wherein the organic solvent
contains a nitrogen-containing solvent; and wherein an element of
the nitrogen-containing solvent to be bonded to nitrogen is
carbon.
20. A cleaning method for a surface of a silicon wafer, using a
cleaning agent for the silicon wafer as claimed in claim 11,
comprising: a step of removing the cleaning agent from the surface
of the silicon wafer after removing the cleaning liquid from the
surface of the silicon wafer.
21. A cleaning method ter a surface of a silicon wafer, as claimed
in claim 20, further comprising: a step of irradiating the surface
of the silicon wafer with light or heating the silicon wafer after
removing the cleaning liquid from the surface of the silicon wafer.
Description
TECHNICAL FIELD
[0001] The present invention relates to a technique of cleaning a
silicon substrate (a wafer) in production of semiconductor devices,
the purpose of which being production yield improvements of devices
having such a circuit pattern as to be particularly fine and to be
a particularly high aspect ratio.
BACKGROUND OF THE INVENTION
[0002] Semiconductor devices for use of network or digital
household electric appliances are being further desired to be
sophisticated, multifunctional and low in power consumption.
Accordingly, the trend toward micro-scale circuit pattern has been
developed, with which micro-sizing of particles is advanced so as
to cause reduction in production yield. As a result of this, a
cleaning process for the purpose of removing the micro-sized
particles is frequently used. As a result of this, 30-40% of the
whole of the fabrication process is occupied with the cleaning
process.
[0003] On the other hand, in a cleaning conventionally performed
with a mixed ammonia cleaning agent, damages to the wafer due to
its basicity becomes more significant with the trend toward
micro-scale pattern circuit. Therefore, alternation with a dilute
hydrofluoric acid-based cleaning agent is taking place.
[0004] With this, the problems about the damages to the wafer due
to cleaning have been solved; however, problems due to an aspect
ratio increased with the trend toward micro-scale pattern in the
semiconductor devices have become obvious. In other words, a
phenomenon where the pattern collapses when a gas-liquid interface
passes through the pattern is brought about after cleaning or
rinsing thereby largely reducing the yield, which has become a
significant problem.
[0005] The pattern collapse occurs at the time of taking the wafer
out of a cleaning liquid or a rinsing liquid. It is said that the
reason thereof is that a difference in height of residual liquid
between a part of high aspect ratio and a part of low aspect ratio
causes a difference in the capillary force which acts on the
pattern.
[0006] Accordingly, it is expected by decreasing the capillary
force that the difference in the capillary force due to the
difference in height of residual liquid is reduced thereby
resolving the pattern collapse. The magnitude of the capillary
force is the absolute value of P obtained by the equation as
represented below. It is expected from this equation that the
capillary force can be reduced if decreasing .gamma. or cos
.theta..
P=2.times..gamma..times.cos .theta./S (.gamma.: Surface tension,
.theta.: Contact angle, S: Pattern width).
[0007] In Patent Document 1, a technique of replacing water as a
cleaning agent with 2-propanol before the gas-liquid interface
passes through the pattern is disclosed as a method of decreasing
.gamma. to suppress the pattern collapse. This method is effective
for preventing the pattern collapse; however, a solvent having
small .gamma. such as 2-propanol and the like is also small in
normal contact angle, which results in the trend to increase cos
.theta.. It is therefore said that there are limitations to
adaptable patterns, for example, an aspect ratio of not higher than
5.
[0008] Additionally, in Patent Document 2, a technique directed to
a resist pattern is disclosed as a method for decreasing cos
.theta. to suppress the pattern collapse. This method is a method
of setting a contact angle to around 90.degree. to bring cos
.theta. close to 0 so as to reduce the capillary force to the limit
thereby suppressing the pattern collapse.
[0009] However, the thus disclosed technique cannot be applied to
the present object, because: it is directed to the resist pattern
or for reforming a resist itself, and a final removal together with
the resist is possible so as not to need the assumption about a
method of removing a treatment agent after drying.
[0010] Additionally, the use of a critical fluid, the use of liquid
nitrogen or the like are proposed as the method of preventing the
pattern collapse in the semiconductor devices. However, any of
these needs a treatment in a closed system or a batch in contrast
to the conventional cleaning processes and therefore involves
issues in view of cost such as throughput, though effective to some
extent.
REFERENCES ABOUT PRIOR ART
Patent Publication
[0011] Patent Publication 1: Japanese Patent Application
Publication No. 2008-198958 [0012] Patent Publication 2: Japanese
Patent Application Publication No. 5-299336
SUMMARY OF THE INVENTION
[0013] In production of semiconductor devices, a surface of a
silicon wafer is a surface having a finely uneven pattern. An
object of the present invention is to provide a silicon wafer
cleaning agent for improving a cleaning process which tends to
induce a pattern collapse, in a method of producing the silicon
wafer having at its surface a finely uneven pattern.
[0014] According to the present invention, there is provided a
cleaning agent for a silicon wafer having a finely uneven pattern
at its surface (a first cleaning agent), the cleaning agent being
characterized in that: the cleaning agent contains at least a
water-based cleaning liquid and a water-repellent cleaning liquid
for providing at least recessed portion of the uneven pattern with
water repellency during a cleaning process; the water-repellent
cleaning liquid is a liquid comprising a water-repellent compound
having a reactive moiety chemically bondable to Si element in the
silicon wafer and a hydrophobic group, or a liquid in which the
water-repellent compound of not lower than 0.1 mass % relative to
the total quantity of 100 mass % of the water-repellent cleaning
liquid and an organic solvent are mixed and contained thereby
presenting a capillary force of not higher than 2.1 MN/m.sup.2 on
the assumption that water is retained in the recessed portion
formed at the surface of the silicon wafer provided with water
repellency by the water-repellent cleaning liquid.
[0015] The water-repellent cleaning agent may be a cleaning agent
for a silicon wafer (A second cleaning agent) characterized in
that: the water-repellent cleaning liquid is a liquid in which the
water-repellent compound and the organic solvent are mixed and
contained; the water-repellent compound is mixed and contained
therein in such an amount as to be 0.1-50 mass % relative to the
total quantity of 100 mass % of the water-repellent cleaning
liquid; the organic solvent contains a nitrogen containing solvent;
the nitrogen containing solvent is a solvent whose element to be
bonded to nitrogen is carbon thereby presenting a capillary force
of not higher than 2.1 MN/m.sup.2 on the assumption that water is
retained in the recessed portion formed at the surface of the
silicon wafer provided with water repellency by the water-repellent
cleaning liquid.
[0016] The following description is a description common between
the first cleaning agent and the second cleaning agent, unless
specified.
[0017] In the cleaning agent of the present invention, each
cleaning liquid is mutually independently used, and at least two or
more kinds of the cleaning liquids are used.
[0018] Additionally, in the present invention, water repellency is
used in a sense that a surface energy of a surface of an article is
decreased thereby reducing an interaction between water or other
liquid and the surface of the article (an interface), such as
hydrogen bond, intermolecular forces and the like. The effect of
reducing an interaction against water is greatly exhibited;
however, the effect of reducing an interaction against a mixture
liquid of water and liquid other than water or against liquid other
than water is also exhibited. With the reduction of the
interaction, it is possible to increase a contact angle of the
liquid to the surface of the article.
[0019] In cleaning the silicon wafer in which an uneven pattern is
formed, the water-based cleaning liquid contained in the silicon
wafer cleaning agent of the present invention is provided to the
surface of the silicon wafer upon making the surface of the silicon
wafer a surface having a finely uneven pattern. Additionally, the
water-based cleaning liquid may be provided to the silicon wafer
through providing the water-repellent cleaning liquid to the
silicon wafer. Furthermore, the water-repellent cleaning liquid and
the water-based cleaning liquid may be provided to the surface of
the silicon wafer while being substituted with a cleaning liquid
different from the cleaning liquids under a condition where the
different cleaning liquid is retained in the recessed portion of
the surface of the silicon wafer.
[0020] The cleaning agent for the silicon wafer of the present
invention is comprised of two or more cleaning liquids and is used
while substituting a cleaning liquid retained in the recessed
portion with another cleaning liquid. The cleaning agent is finally
removed from the surface of the silicon wafer.
[0021] While the surface of the silicon wafer is cleaned by the
cleaning agent for the silicon wafer of the present invention, the
recessed portion of the surface of the silicon wafer is to
temporarily retain the water-repellent cleaning liquid. With this
retention, the recessed portion is brought into a surface condition
provided with water repellency by the water-repellent compound.
[0022] In the present invention, the water-repellent compound has a
reactive moiety chemically bondable to Si element in the silicon
wafer, and a hydrophobic group. With this, the surface of the
silicon wafer can keep the surface condition provided with water
repellency. Since the surface of the recessed portion is under the
condition provided with water repellency, the capillary force at
the time of removing or drying the cleaning liquid is so reduced
that the pattern collapse becomes hard to occur. Additionally, the
surface condition provided with water repellency can be removed by
irradiating the surface of the silicon wafer with light or heating
the silicon wafer.
[0023] If the water-repellent compound contained in the
water-repellent cleaning liquid is less than 0.1 mass % relative to
the total quantity of 100 mass % of the water-repellent cleaning
liquid, the surface of the recessed portion cannot sufficiently
obtain the surface condition provided with water repellency.
[0024] Additionally, the water-repellent cleaning liquid in the
first cleaning agent contains a mixture of; the water-repellent
compound having a reactive moiety chemically bondable to Si element
in the silicon wafer and a hydrophobic group; and the organic
solvent, so that the surface of the recessed portion can readily
reach the surface condition sufficiently provided with water
repellency with a short period of time.
[0025] Additionally, the second cleaning agent is those of which
element to be bonded to nitrogen is carbon. With this, the surface
of the recessed portion can readily reach the surface condition
sufficiently provided with water repellency with a short period of
time.
BRIEF EXPLANATION OF THE DRAWINGS
[0026] FIG. 1 A schematic plan view of a silicon wafer 1 of which
surface is made a surface having a finely uneven pattern 2.
[0027] FIG. 2 A view showing a part of a-a' cross section of FIG.
1.
[0028] FIG. 3 A schematic view showing a condition where a cleaning
liquid 8 is retained in a recessed portion 4 in a cleaning
process.
[0029] FIG. 4 A schematic view showing a condition where a
water-based cleaning liquid is retained in the recessed portion 4
which is under a surface condition provided with water
repellency.
DETAILED DESCRIPTION
[0030] A silicon wafer cleaning agent of the present invention
exhibits an excellent pattern collapse-preventability. When using
the cleaning agent, therefore, a cleaning process of a production
method for a silicon wafer having a finely uneven pattern at its
surface is improved without reducing throughput. With this, the
productivity of the production method conducted by using the
silicon wafer cleaning agent of the present invention on the
silicon wafer having the finely uneven pattern at its surface is
increased.
[0031] The silicon wafer cleaning agent of the present invention is
adaptable to uneven patterns with increasingly growing aspect
ratios, for example, an aspect ratio of not less than 7, and allows
cost reduction in producing more sophisticated semiconductor
devices. In addition to this, the agent is adaptable without
considerably modifying conventional apparatuses, which results in
adaptable one to production of various kinds of semiconductor
devices.
[0032] A cleaning method for the silicon wafer having the finely
uneven pattern at its surface, using the silicon wafer cleaning
agent of the present invention, preferably includes:
[0033] a step of making a silicon wafer have a surface with a
finely uneven pattern, followed by providing a water-based cleaning
liquid to the surface and retaining the water-based cleaning liquid
in recessed portions;
[0034] a step of substituting the water-based cleaning liquid
retained in the recessed portions with a cleaning liquid A
different from the water-based cleaning liquid;
[0035] a step of retaining a water-repellent cleaning liquid in the
recessed portions in order to make surfaces of the recessed
portions of the uneven pattern have water repellency; and
[0036] a step of removing the cleaning agent.
[0037] Furthermore, after the step of retaining the water-repellent
cleaning liquid in the recessed portions, the water-repellent
cleaning liquid retained in the recessed portions may be
substituted with a cleaning liquid B different from the
water-repellent cleaning liquid. Additionally, it is more
preferable to take a step of retaining a water-based cleaning
liquid comprised of a water-based solution in the recessed portions
through the substitution with the different cleaning liquid.
[0038] Additionally, the step of removing the cleaning agent
includes:
[0039] a step of removing the cleaning liquid retained in the
recessed portions from the recessed portions by drying; and
[0040] a step of irradiating the surface of the silicon wafer with
light or heating the silicon wafer.
[0041] Additionally, in the step of removing the cleaning agent,
between the step of removing the cleaning liquid retained in the
recessed portions from the recessed portions by drying and the step
of irradiating the surface of the silicon wafer with light or
heating the silicon wafer, there may be taken: a step of providing
the cleaning liquid B to the recessed portions and then removing
the cleaning liquid B by drying; or a step of retaining the
water-based cleaning liquid comprised of the water-based solution
in the recessed portions after providing the cleaning liquid B,
followed by removing the water-based cleaning liquid by drying.
[0042] In a first cleaning agent, the water-repellent cleaning
liquid is a liquid comprising a water-repellent compound having a
reactive moiety which can chemically bind with Si element in the
silicon wafer and a hydrophobic group, or a liquid in which the
water-repellent compound of not less than 0.1 mass % relative to
the total quantity of 100 mass % of the water-repellent cleaning
liquid and an organic solvent are mixed and contained.
Incidentally, a larger content of the water-repellent compound
tends to make it difficult to bring the surfaces of the recessed
portions into a surface condition of homogeneous water repellency,
while a smaller content thereof tends to make it difficult to bring
the surfaces of the recessed portions into a surface condition of
sufficient water repellency in a short time. Therefore, the
water-repellent compound is preferably 0.2-50 mass % and
particularly preferably 0.2-30 mass % relative to the total
quantity of 100 mass % of the water-repellent cleaning liquid.
[0043] In a second cleaning agent, the water-repellent cleaning
liquid is a liquid in which the water-repellent compound of 0.1-50
mass % relative to the total quantity of 100 mass % of the
water-repellent cleaning liquid and an organic solvent is mixed and
contained. Incidentally, a larger content of the water-repellent
compound tends to make it difficult to bring the surfaces of the
recessed portions into a surface condition of a homogeneous water
repellency, while a smaller content thereof tends to make it
difficult to bring the surfaces of the recessed portions into a
surface condition of sufficient water repellency in a short time.
Therefore, the water-repellent compound is preferably 0.1-50 mass %
and particularly preferably 0.2-30 mass % relative to the total
quantity of 100 mass % of the water-repellent cleaning liquid.
[0044] In the second cleaning agent, the organic solvent contains a
nitrogen containing solvent whose element to be bonded to nitrogen
is carbon. With the nitrogen containing solvent, a reaction between
the water-repellent compound and Si element in the silicon wafer is
accelerated so as to tend to readily bring the surfaces of the
recessed portions of the silicon wafer into the surface condition
of sufficient water repellency in a short time. Additionally, it is
preferable that the nitrogen containing solvent is at least one
selected from the group consisting of tertiary amide, tertiary
amine, 1-alkyl-2-pyrrolidone and compounds having pyridine
ring.
[0045] Concrete examples of the nitrogen containing solvent are
N,N-dimethylformamide, N,N-dimethylacetamide, triethylamine,
tripropylamine, N-methyl-2-pyrrolidone, pyridine, pyrazine,
picoline and the like. In particular, N,N-dimethylformamide and
N-methyl-2-pyrrolidone are preferable because these are hard to
form an insoluble solid when mixed with the water-repellent
compound.
[0046] The nitrogen containing solvent is preferably not less than
0.0005 mass %, more preferably not less than 0.001 mass %, much
more preferably not less than 0.005 mass % relative to the total
quantity of 100 mass % of the water-repellent cleaning liquid. The
nitrogen containing solvent of not less than 0.0005 mass % can
readily bring the surfaces of the recessed portions of the silicon
wafer into the surface condition of sufficient water repellency in
a short time.
[0047] In the pattern forming step of making the surface of the
silicon wafer a surface having a finely uneven pattern, a resist is
applied to the surface of the wafer first of all. Thereafter, the
resist is exposed through a resist mask, followed by conducting an
etching removal on an exposed resist or a unexposed resist, thereby
producing a resist having a desired uneven pattern. Additionally,
the resist having the uneven pattern can be obtained also by
pushing a mold having a pattern onto a resist. Then, etching is
conducted on the wafer. At this time, recessed portions of a resist
pattern are etched selectively. Finally, the resist is stripped off
thereby obtaining a silicon wafer having a finely uneven
pattern.
[0048] Incidentally, the silicon wafer includes those on which
surface a silicon oxide film such as native oxide film, a thermal
oxide film, a gas-phase synthesized film (a CVD film, etc.) and the
like is formed or those in which at least a part of its uneven
pattern is to be silicon oxide when forming the uneven pattern.
[0049] Additionally, also against a wafer comprised of two or more
components including silicon and/or silicon oxide, it is possible
to provide its surface of silicon and/or silicon oxide with water
repellency. The wafer comprised of two or more components includes
those on which surface a film of silicon and/or silicon oxide such
as a native oxide film, a thermal oxide film, a gas-phase
synthesized film (a CVD film, etc.) and the like is formed or those
in which at least a part of its uneven pattern is to be silicon
and/or silicon oxide when forming the uneven pattern.
[0050] After making the surface of the silicon wafer a surface
having a finely uneven pattern, cleaning of the surface is
conducted in the use of the water-repellent cleaning liquid,
followed by removing the water-repellent cleaning liquid by drying
or the like. However, if the recessed portions have a small width
and projected portions have a large aspect ratio, a pattern
collapse is to be easily induced. The uneven pattern is defined as
shown in FIG. 1 and FIG. 2. FIG. 1 is a schematic plan view of a
silicon wafer 1 whose surface is made a surface having a finely
uneven pattern, while FIG. 2 is a part of an a-a' cross section in
FIG. 1. A width 5 of a recessed portion is defined by an interval
between a projected portion 3 and a projected portion 3, as shown
in FIG. 2. The aspect ratio of the projected portion is expressed
by dividing a height 6 of the projected portion by a width 7 of the
recessed portion. The pattern collapse in the cleaning process is
easily induced when the recessed portion has a width of not more
than 70 nm, particularly not more than 45 nm and when the aspect
ratio is not less than 4, particularly not less than 6.
[0051] In a preferable example of the present invention, the
surface of the silicon wafer is made a surface having an uneven
pattern, followed by providing the water-based cleaning liquid on
the surface and then retaining the water-based cleaning liquid in
the recessed portions. Then, the water based cleaning liquid
retained in the recessed portions is substituted with the cleaning
liquid A different from the water-based cleaning liquid. Preferable
examples of the different cleaning liquid A are: the
water-repellent cleaning liquid specified by the present invention;
water; an organic solvent; a mixture of these; a mixture of these
and at least one or more kinds of acid, alkali and surfactant; and
the like. Additionally, when using other than the water-repellent
cleaning liquid as the different cleaning liquid A, it is
preferable to substitute the different cleaning liquid A with the
water-repellent cleaning liquid under a condition where the
different cleaning liquid A is retained in recessed portions 4.
[0052] Additionally, examples of the organic solvent, one of
preferable examples of the different cleaning liquid A, are
hydrocarbons, esters, ethers, ketones, halogen-containing solvents,
sulfoxide-based solvents, alcohols, derivatives of polyhydric
alcohol, nitrogen containing solvents, and the like.
[0053] Additionally, it is particularly preferable that the organic
solvent, one of preferable examples of the different cleaning
liquid A, is an aprotic solvent since the water-repellent compound
is reactive with a protic solvent. Incidentally, the aprotic
solvent means both an aprotic polar solvent and an aprotic nonpolar
solvent. Examples of such an aprotic solvent include hydrocarbons,
esters, ethers, ketones, halogen-containing solvents,
sulfoxide-based solvents, derivatives of polyhydric alcohol having
no hydroxyl group, and nitrogen containing solvents having no N--H
bond. Examples of the hydrocarbons are toluene, benzene, xylene,
hexane, heptane, octane and the like. Examples of the esters are
ethyl acetate, propyl acetate, butyl acetate, ethyl acetoacetate
and the like. Examples of the ethers are diethyl ether, dipropyl
ether, dibutyl ether, tetrahydrofuran, dioxane and the like.
Examples of the ketones are acetone, acetylacetone, methyl ethyl
ketone, methyl propyl ketone, methyl butyl ketone and the like.
Examples of the halogen-containing solvent are: perfluorocarbons
such as perfluorooctane, perfluorononane, perfluorocyclopentane,
perfluorocyclohexane, hexafluorobenzene and the like;
hydrofluorocarbons such as 1,1,1,3,3-pentafluorobutane,
octafluorocyclopentane, 2,3-dihydrodecafluoropentane, ZEORORA-H
(produced by ZEON CORPORATION) and the like; hydrofluoroethers such
as methyl perfluoroisobutyl ether, methyl perfluorobutyl ether,
ethyl perfluorobutyl ether, ethyl perfluoroisobutyl ether,
ASAHIKLIN AE-3000 (produced by Asahi Glass Co., Ltd.), Novec
HFE-7100, Novec HFE-7200, Novec 7300, Novec 7600 (any is produced
by 3M Limited) and the like; chlorocarbons such as
tetrachloromethane and the like; hydrochlorocarbons such as
chloroform and the like; chlorofluorocarbons such as
dichlorodifluoromethane and the like; hydrochlorofluorocarbons such
as 1,1-dichloro-2,2,3,3,3-pentafluoropropane,
1,3-dichloro-1,1,2,2,3-pentafluoropropane,
1-chloro-3,3,3-trifluoropropene,
1,2-dichloro-3,3,3-trifluoropropene and the like; perfluoroethers;
perfluoropolyethers; and the like. Examples of the sulfoxide-based
solvents are dimethyl sulfoxide and the like. Examples of the
derivatives of polyhydric alcohol having no hydroxyl group are
acetate-based compounds such as diethylene glycol monoethyl ether
acetate, ethylene glycol monomethyl ether acetate, ethylene glycol
monobutyl ether acetate, propylene glycol monomethyl ether acetate,
propylene glycol monoethyl ether acetate and the like. Examples of
the nitrogen containing solvents having no N--H bond are
N,N-dimethylformamide, N,N-dimethylacetamide,
N-methyl-2-pyrrolidone, triethylamine, pyridine and the like.
[0054] FIG. 3 is a schematic view showing a condition where a
cleaning liquid 8 is retained in the recessed portions 4 in the
cleaning process. A silicon wafer of the schematic view of FIG. 1
shows a part of the a-a' cross section in FIG. 1. At the time of
the cleaning process, the water-repellent cleaning liquid is
provided onto a silicon wafer 1 in which an uneven pattern 2 is
formed. At this time, the water-repellent cleaning liquid is
brought into a condition retained at least in the recessed portions
4 as shown in FIG. 3, thereby imparting water repellency to the
recessed portions 4.
[0055] In a case of providing the water-based cleaning liquid
through the substitution of the water-repellent cleaning liquid
under a condition temporarily retained in the recessed portions 4
with a cleaning liquid different from the cleaning liquid, the
water-repellent cleaning liquid retained in the recessed portions 4
is substituted with the cleaning liquid B different from the
water-repellent cleaning liquid. Examples of the different cleaning
liquid B are: water-based cleaning liquids comprised of a
water-based solution; an organic solvent; a mixture of the
water-based cleaning liquid and the organic solvent; a mixture of
these and at least one or more kinds of acid, alkali and
surfactant; and the like. Particularly, the water-based cleaning
liquid, the organic solvent or the mixture of the water-based
cleaning liquid and the organic solvent is preferable.
Additionally, when using other than the water-based cleaning liquid
as the different cleaning liquid B, it is preferable to substitute
the cleaning liquid with the water-based cleaning liquid under a
condition where the cleaning liquid other than the water-based
cleaning liquid is retained in the recessed portions 4.
[0056] Additionally, examples of the organic solvent, one of
preferable examples of the different cleaning liquid B, are
hydrocarbons, esters, ethers, ketones, halogen-containing solvents,
sulfoxide-based solvents, alcohols, derivatives of polyhydric
alcohol, nitrogen containing solvents and the like.
[0057] Examples of the hydrocarbons are toluene, benzene, xylene,
hexane, heptane, octane and the like. Examples of the esters are
ethyl acetate, propyl acetate, butyl acetate, ethyl acetoacetate
and the like. Examples of the ethers are diethyl ether, dipropyl
ether, dibutyl ether, tetrahydrofuran, dioxane and the like.
Examples of the ketones are acetone, acetylacetone, methyl ethyl
ketone, methyl propyl ketone, methyl butyl ketone and the like.
Examples of the halogen-containing solvent are: perfluorocarbons
such as perfluorooctane, perfluorononane, perfluorocyclopentane,
perfluorocyclohexane, hexafluorobenzene and the like;
hydrofluorocarbons such as 1,1,1,3,3-pentafluorobutane,
octafluorocyclopentane, 2,3-dihydrodecafluoropentane, ZEORORA-H
(produced by ZEON CORPORATION) and the like; hydrofluoroethers such
as methyl perfluoroisobutyl ether, methyl perfluorobutyl ether,
ethyl perfluorobutyl ether, ethyl perfluoroisobutyl ether,
ASAHIKLIN AE-3000 (produced by Asahi Glass Co., Ltd.), Novec
HFE-7100, Novec HFE-7200, Novec 7300, Novec 7600 (any is produced
by 3M Limited) and the like; chlorocarbons such as
tetrachloromethane and the like; hydrochlorocarbons such as
chloroform and the like; chlorofluorocarbons such as
dichlorodifluoromethane and the like; hydrochlorofluorocarbons such
as 1,1-dichloro-2,2,3,3,3-pentafluoropropane,
1,3-dichloro-1,1,2,2,3-pentafluoropropane,
1-chloro-3,3,3-trifluoropropene,
1,2-dichloro-3,3,3-trifluoropropene and the like; perfluoroethers;
perfluoropolyethers; and the like. Examples of the sulfoxide-based
solvents are dimethyl sulfoxide and the like. Examples of the
alcohols are methanol, ethanol, propanol, butanol, ethylene glycol,
1,3-propanediol and the like. Examples of the derivatives of
polyhydric alcohol are acetate-based compounds such as diethylene
glycol monoethyl ether, ethylene glycol monomethyl ether, ethylene
glycol monobutyl ether, propylene glycol monomethyl ether,
propylene glycol monoethyl ether, diethylene glycol monoethyl ether
acetate, ethylene glycol monomethyl ether acetate, ethylene glycol
monobutyl ether acetate, propylene glycol monomethyl ether acetate,
propylene glycol monoethyl ether acetate and the like. Examples of
the nitrogen containing solvents are formamide,
N,N-dimethylformamide, N,N-dimethylacetamide,
N-methyl-2-pyrrolidone, diethylamine, triethylamine, pyridine and
the like.
[0058] An example of the water-based cleaning liquid is water, or
one containing water with which at least one or more kinds of an
organic solvent, acid and alkali is mixed as its main component
(for example, a water content of not smaller than 50 mass %).
Particularly, the use of water for the water-based cleaning liquid
increases a contact angle .theta. formed between the surface of the
recessed portions provided with water repellency by the
water-repellent cleaning liquid and the liquid, so as to reduce the
capillary force P and further to make stains hard to remain on the
surface of the wafer after drying, which is therefore
preferable.
[0059] A schematic view of a case in which the water-based cleaning
liquid is retained in the recessed portions 4 provided with water
repellency by the water-repellent compound is shown in FIG. 4. A
silicon wafer of the schematic view of FIG. 4 shows a part of the
a-a' cross section in FIG. 1. The surfaces of the recessed portions
4 are brought into a surface condition 10 provided with water
repellency by the water-repellent compound. Then, with an unit
chemically bondable to Si, the surface condition 10 provided with
water repellency is kept on the surface of the silicon wafer even
when the water-based cleaning liquid 9 is removed from the recessed
portions 4.
[0060] The capillary force is, on the assumption that the surface
of recessed portions formed at the silicon wafer surface provided
with water repellency by the water-repellent cleaning liquid, i.e.
the recessed portions 4 as shown in FIG. 4 is brought into the
surface condition 10 and that water is retained in the recessed
portions, preferably not greater than 2.1 MN/m.sup.2. A capillary
force of not greater than 2.1 MN/m.sup.2 makes the pattern collapse
difficult to occur, and therefore is preferable. Additionally, when
a smaller the capillary force makes the pattern collapse further
difficult to occur, so that the capillary force is particularly
preferably not greater than 1.5 MN/m.sup.2, much more preferably
not greater than 1.0 MN/m.sup.2. Furthermore, it is ideal to put
the capillary force to 0.0 MN/m.sup.2 as close as possible by
adjusting the contact angle to the cleaning liquid to be around
90.degree..
[0061] Additionally, in the water-repellent compound of the
water-repellent cleaning liquid, having the reactive moiety which
can chemically bind with Si element in the silicon wafer and a
hydrophobic group, the reactive moiety is exemplified by those who
can react with silanol group (Si--OH group). Examples thereof are:
halogen group such as chloro group, bromo group and the like; Si--N
bond with isocyanate group, amino group, dialkylamino group,
isothiocyanate group, azide group, acetamide group, silazane,
--N(CH.sub.3)COCH.sub.3, --N(CH.sub.3)COCF.sub.3, imidazole ring,
oxazolidinone ring, morpholine ring or the like; Si--O--C bond with
alkoxy group, acetoxy group, trifluoroacetoxy group,
--OC(CH.sub.3).dbd.CHCOCH.sub.3,
--OC(CH.sub.3).dbd.N--Si(CH.sub.3).sub.3,
--OC(CF.sub.3).dbd.N--Si(CH.sub.3).sub.3,
--CO--NH--Si(CH.sub.3).sub.3 or the like; Si--O--S bond with
alkylsulfonate group, perfluoroalkylsulfonate group or the like;
nitrile group; and the like. Additionally, examples of the
hydrophobic group are a monovalent organic group having hydrocarbon
group and a monovalent organic group having C--F bond. Such a
water-repellent compound is to swiftly react at its reactive moiety
with silanol group of a silicon oxide layer of the uneven pattern
of the silicon wafer so as to be chemically bonded to Si element in
the silicon wafer through siloxane bond. With this, it becomes
possible to coat the surface of the wafer with hydrophobic groups,
thereby allowing reducing the capillary force in a short time.
[0062] Furthermore, it is preferable, in the water-repellent
cleaning liquid, that the water-repellent compound having the
reactive moiety chemically bondable to Si element in the silicon
wafer and the hydrophobic group is comprised of at least one
selected from the group consisting of the following general
formulas [1], [2] and [3].
(R.sup.1).sub.aSi(CH.sub.3).sub.bH.sub.cX.sub.4-a-b-c [1]
[R.sup.2Si(CH.sub.3).sub.2-dH.sub.d].sub.eNH.sub.3-e [2]
R.sup.3Si(CH.sub.3).sub.2Y [3]
[0063] Now, each of R.sup.1, R.sup.2 and R.sup.3 is a monovalent
organic group having hydrocarbon group with a carbon number of 1 to
18 or a monovalent organic group having perfluoroalkyl chain with a
carbon number of 1 to 8. X represents chloro group, isocyanate
group, alkoxy group, acetoxy group, trifluoroacetoxy group,
--OC(CH.sub.3).dbd.CHCOCH.sub.3, alkylsulfonate group,
perfluoroalkylsulfonate group, or nitrile group. Y represents a
monovalent organic group whose element to be bonded to Si is
nitrogen. a is an integer of from 1 to 3 while b and c are integers
of from 0 to 2, and the total of a, b and c is from 1 to 3.
Furthermore, d is an integer of from 0 to 2 and e is an integer of
from 1 to 3.
[0064] Additionally, it is particularly preferable that each of
R.sup.1 of the general formula [1], R.sup.2 of the general formula
[2], and R.sup.3 of the general formula [3] is C.sub.mH.sub.2m+1
(m=1-18) or C.sub.nF.sub.2n+1CH.sub.2CH.sub.2 (n=1-8).
[0065] Examples of usable water-repellent compound represented by
the general formula [1] are: alkylchlorosilane such as
C.sub.18H.sub.37SiCl.sub.3, C.sub.10H.sub.21SiCl.sub.3,
C.sub.6H.sub.13SiCl.sub.3, C.sub.3H.sub.7SiCl.sub.3,
CH.sub.3SiCl.sub.3, C.sub.18H.sub.37Si(CH.sub.3)Cl.sub.2,
C.sub.10H.sub.21Si(CH.sub.3)Cl.sub.2,
C.sub.6H.sub.13Si(CH.sub.3)Cl.sub.2,
C.sub.3H.sub.7Si(CH.sub.3)Cl.sub.2, (CH.sub.3).sub.2SiCl.sub.2,
C.sub.18H.sub.37Si(CH.sub.3).sub.2Cl,
C.sub.10H.sub.21Si(CH.sub.3).sub.2Cl,
C.sub.6H.sub.13Si(CH.sub.3).sub.2Cl,
C.sub.3H.sub.7Si(CH.sub.3).sub.2Cl, (CH.sub.3).sub.3SiCl,
(CH.sub.3).sub.2SiHCl and the like; fluoroalkylchlorosilane such as
C.sub.8F.sub.17CH.sub.2CH.sub.2SiCl.sub.3,
C.sub.6F.sub.13CH.sub.2CH.sub.2SiCl.sub.3,
C.sub.4F.sub.9CH.sub.2CH.sub.2SiCl.sub.3,
CF.sub.3CH.sub.2CH.sub.2SiCl.sub.3,
C.sub.8F.sub.17CH.sub.2CH.sub.2Si(CH.sub.3)Cl.sub.2,
C.sub.6F.sub.13CH.sub.2CH.sub.2Si(CH.sub.3)Cl.sub.2,
C.sub.4F.sub.9CH.sub.2CH.sub.2Si(CH.sub.3)Cl.sub.2,
CF.sub.3CH.sub.2CH.sub.2Si(CH.sub.3)Cl.sub.2,
C.sub.8F.sub.17CH.sub.2CH.sub.2Si(CH.sub.3).sub.2Cl,
C.sub.6F.sub.13CH.sub.2CH.sub.2Si(CH.sub.3).sub.2Cl,
C.sub.4F.sub.9CH.sub.2CH.sub.2Si(CH.sub.3).sub.2Cl,
CF.sub.3CH.sub.2CH.sub.2Si(CH.sub.3).sub.2Cl,
CF.sub.3CH.sub.2CH.sub.2Si(CH.sub.3)HCl and the like; or a
water-repellent compound in which chloro group of the
above-mentioned chlorosilane is replaced with isocyanate group,
alkoxy group, acetoxy group, trifluoroacetoxy group,
--OC(CH.sub.3).dbd.CHCOCH.sub.3, alkylsulfonate group,
perfluoroalkylsulfonate group, or nitrile group. The particularly
preferable are chloro group, isocyanate group and alkoxy group.
[0066] Examples of usable water-repellent compound represented by
the general formula [2] are (CH.sub.3).sub.3SiNHSi(CH.sub.3).sub.3,
C.sub.2H.sub.5Si(CH.sub.3).sub.2NHSi(CH.sub.3).sub.2C.sub.2H.sub.5,
C.sub.3H.sub.7Si(CH.sub.3).sub.2NHSi(CH.sub.3).sub.2C.sub.3H.sub.7,
C.sub.6H.sub.13Si(CH.sub.3).sub.2NHSi(CH.sub.3).sub.2C.sub.6H.sub.13,
C.sub.6H.sub.5Si(CH.sub.3).sub.2NHSi(CH.sub.3).sub.2C.sub.6H.sub.5,
{(CH.sub.3).sub.3Si}.sub.3N,
{C.sub.2H.sub.5Si(CH.sub.3).sub.2}.sub.3N,
(CH.sub.3).sub.2HSiNHSi(CH.sub.3).sub.2H,
CF.sub.3CH.sub.2CH.sub.2Si(CH.sub.3).sub.2NHSi(CH.sub.3).sub.2CH.sub.2CH.-
sub.2CF.sub.3,
C.sub.4F.sub.9CH.sub.2CH.sub.2Si(CH.sub.3).sub.2NHSi(CH.sub.3).sub.2CH.su-
b.2CH.sub.2C.sub.4F.sub.9,
C.sub.6F.sub.13CH.sub.2CH.sub.2Si(CH.sub.3).sub.2NHSi(CH.sub.3).sub.2CH.s-
ub.2CH.sub.2C.sub.6F.sub.13,
C.sub.8F.sub.17CH.sub.2CH.sub.2Si(CH.sub.3).sub.2NHSi(CH.sub.3).sub.2CH.s-
ub.2CH.sub.2C.sub.8F.sub.17,
{CF.sub.3CH.sub.2CH.sub.2Si(CH.sub.3).sub.2}.sub.3N, and the like.
Particularly, disilazane where d in the general formula [2] is 2 is
preferable.
[0067] Furthermore, examples of usable water-repellent compound
represented by the general formula [2] are compounds where Y is
--NH.sub.2, --N(CH.sub.3).sub.2, --N(C.sub.2H.sub.5).sub.2,
--NHCOCH.sub.3, --N.sub.3, --N.dbd.C.dbd.S,
--N(CH.sub.3)COCH.sub.3, --N(CH.sub.3)COCF.sub.3,
--N.dbd.C(CH.sub.3)OSi(CH.sub.3).sub.3,
--N.dbd.C(CF.sub.3)OSi(CH.sub.3).sub.3,
--NHCO--OSi(CH.sub.3).sub.3, --NHCO--NH--Si(CH.sub.3).sub.3,
imidazole ring, oxazolidinone ring, morpholine ring or the
like.
[0068] Additionally, if water is present in the water-repellent
cleaning liquid, the reactive moiety of the water-repellent
compound is hydrolyzed to be silanol group (Si--OH). The reactive
moiety is reactive with this silanol group. As a result,
water-repellent compounds are bonded to each other to be a dimer.
The dimer is low in reactivity with silanol group in the silicon
oxide layer of the silicon wafer, so that the time required to
provide the surface of the silicon wafer with water repellency is
increased. As the solvent for the water-repellent cleaning liquid,
therefore, other than water, i.e. the organic solvent is used. The
organic solvent is acceptable if able to dissolve the
water-repellent compound therein; and preferably usable examples
thereof are hydrocarbons, esters, ethers, ketones,
halogen-containing solvents, sulfoxide-based solvents, alcohols,
derivatives of polyhydric alcohol, nitrogen containing solvents,
and the like.
[0069] However, using the aprotic solvent as the organic solvent
since the water-repellent compound is reactive with the protic
solvent is particularly preferable because water repellency becomes
readily exhibited in a short time. Incidentally, the aprotic
solvent means both an aprotic polar solvent and an aprotic nonpolar
solvent. Examples of such an aprotic solvent include hydrocarbons,
esters, ethers, ketones, halogen-containing solvents,
sulfoxide-based solvents, derivatives of polyhydric alcohol having
no hydroxyl group, and nitrogen containing solvents having no N--H
bond. Examples of the hydrocarbons are toluene, benzene, xylene,
hexane, heptane, octane and the like. Examples of the esters are
ethyl acetate, propyl acetate, butyl acetate, ethyl acetoacetate
and the like. Examples of the ethers are diethyl ether, dipropyl
ether, dibutyl ether, tetrahydrofuran, dioxane and the like.
Examples of the ketones are acetone, acetylacetone, methyl ethyl
ketone, methyl propyl ketone, methyl butyl ketone and the like.
Examples of the halogen-containing solvent are: perfluorocarbons
such as perfluorooctane, perfluorononane, perfluorocyclopentane,
perfluorocyclohexane, hexafluorobenzene and the like;
hydrofluorocarbons such as 1,1,1,3,3-pentafluorobutane,
octafluorocyclopentane, 2,3-dihydrodecafluoropentane, ZEORORA-H
(produced by ZEON CORPORATION) and the like; hydrofluoroethers such
as methyl perfluoroisobutyl ether, methyl perfluorobutyl ether,
ethyl perfluorobutyl ether, ethyl perfluoroisobutyl ether,
ASAHIKLIN AE-3000 (produced by Asahi Glass Co., Ltd.), Novec
HFE-7100, Novec HFE-7200, Novec 7300, Novec 7600 (any is produced
by 3M Limited) and the like; chlorocarbons such as
tetrachloromethane and the like; hydrochlorocarbons such as
chloroform and the like; chlorofluorocarbons such as
dichlorodifluoromethane and the like; hydrochlorofluorocarbons such
as 1,1-dichloro-2,2,3,3,3-pentafluoropropane,
1,3-dichloro-1,1,2,2,3-pentafluoropropane,
1-chloro-3,3,3-trifluoropropene,
1,2-dichloro-3,3,3-trifluoropropene and the like; perfluoroethers;
perfluoropolyethers; and the like. Examples of the sulfoxide-based
solvents are dimethyl sulfoxide and the like. Examples of the
derivatives of polyhydric alcohol having no hydroxyl group are
acetate-based compounds such as diethylene glycol monoethyl ether
acetate, ethylene glycol monomethyl ether acetate, ethylene glycol
monobutyl ether acetate, propylene glycol monomethyl ether acetate,
propylene glycol monoethyl ether acetate and the like. Examples of
the nitrogen containing solvents having no N--H bond are
N,N-dimethylformamide, N,N-dimethylacetamide,
N-methyl-2-pyrrolidone, triethylamine, pyridine and the like.
[0070] Additionally, it is preferable to use a uninflammable one as
the organic solvent since the water-repellent cleaning liquid
becomes uninflammable or becomes high in flash point to reduce the
risk of the water-repellent cleaning liquid. The halogen-containing
solvent is large in number of the uninflammable one. Such a
halogen-containing uninflammable solvent can be preferably used as
a uninflammable organic solvent.
[0071] Additionally, a very small quantity of water may be present
in the organic solvent. However, when the water is contained in the
solvent in large quantity, the water-repellent compound is
hydrolyzed by the water so as to be sometimes reduced in
reactivity. It is, therefore, preferable to set the water content
in the solvent low. The water content at the time of being mixed
with the water-repellent compound is preferably less than 1 mole,
particularly preferably less than 0.5 mole relative to the
water-repellent compound in mole ratio.
[0072] Additionally, a catalyst may be added to the water-repellent
cleaning liquid in order to accelerate the reaction between the
water-repellent compound and the wafer surface. The preferably used
as such a catalyst are: acids containing no water such as
trifluoroacetic acid, trifluoroacetic anhydride,
pentafluoropropionic acid, pentafluoropropionic anhydride,
trifluoromethanesulfonic acid, trifluoromethanesulfonic anhydride,
sulfuric acid, hydrogen chloride and the like; bases such as
ammonia, alkylamine, dialkylamine and the like; nitrogen-containing
aprotic solvents pyridine, dimethylformamide and the like; salts
such as ammonium sulfide, potassium acetate, methylhydroxyamine
hydrochloride; and a metallic complex or a metallic salt of tin,
aluminum, titanium or the like. Particularly, if taking a catalytic
effect and cleanliness into account, the preferable are acids
containing no water, such as trifluoroacetic acid, trifluoroacetic
anhydride, trifluoromethanesulfonic acid, trifluoromethanesulfonic
anhydride, sulfuric acid, hydrogen chloride and the like.
[0073] The added amount of the catalyst is preferably from 0.001 to
5 mass % relative to the total quantity of 100 mass % of the
water-repellent compound. The catalytic effect is reduced when the
added amount is small, so that it is not preferable. Additionally,
excessively increased catalyst can cause a fear of eroding the
wafer surface or remaining as impurity on the wafer, rather than
improves the catalytic effect. The added amount of the catalyst is,
therefore, preferably from 0.001 to 5 mass %.
[0074] Moreover, if the temperature is increased, the
water-repellent cleaning liquid becomes liable to bring about a
surface condition where the surfaces of the recessed portions are
provided with water repellency, in a short time. The temperature
liable to bring about a surface condition homogeneously provided
with water repellency is preferably kept at 10 to 160.degree. C.,
particularly at 15 to 120.degree. C. It is preferable to keep the
temperature of the water-repellent cleaning liquid at the
temperature also when the water-repellent cleaning liquid is
retained in the recessed portions 4.
[0075] Then, a step of removing the cleaning liquid retained in the
recessed portions 4 provided with water repellency by the
water-repellent compound, followed by removing the cleaning agent,
is conducted. This step preferably includes:
[0076] a step of removing the cleaning liquid retained in the
recessed portions from the recessed portions by drying; and
[0077] a step of irradiating the surface of the silicon wafer with
light or heating the silicon wafer.
[0078] At the time of removing the cleaning liquid from the
recessed portions, the cleaning liquid retained in the recessed
portions is preferably the water-based cleaning liquid. In this
case, it is preferable to conduct a step of retaining the
water-based cleaning liquid comprised of the water-based solution
in the recessed portions after the step of retaining the
water-repellent cleaning liquid in the recessed portions, through
the substitution of the water-repellent cleaning liquid retained in
the recessed portions with the cleaning liquid B different from the
water-repellent cleaning liquid. Incidentally, when the cleaning
liquid is removed from the recessed portions, the cleaning liquid
retained in the recessed portions may be the water-repellent
cleaning liquid or the different cleaning liquid B.
[0079] In the step of removing the cleaning liquid from the
recessed portions, the cleaning liquid is removed by drying. The
drying is preferably conducted by a conventional drying method such
as spin drying, IPA (2-propanol) steam drying, Marangoni drying,
heating drying, warm air drying, vacuum drying and the like.
[0080] In the step of irradiating the surface of the silicon wafer
with light or heating the silicon wafer, the surface condition 10
where the surface of the silicon wafer is provided with water
repellency is removed.
[0081] In the case where the surface condition 10 provided with
water repellency is removed by light irradiation, it is effective
to cleave Si--C bond, C--C bond and C--F bond in the surface
condition 10 provided with water repellency by the water-repellent
compound. In order to achieve this, it is preferable to conduct an
irradiation with ultraviolet rays having wavelengths of 350-450 nm,
340 nm and shorter than 240 nm (corresponding to bond energies of
them, i.e., 58-80 kcal/mol, 83 kcal/mol and 116 kcal/mol). As the
light source therefor, there is used a metal halide lamp, a
low-pressure mercury light, a high-pressure mercury light, an
excimer lamp, a carbon arc or the like. The intensity of the
ultraviolet irradiation is preferably not less than 100
mW/cm.sup.2, particularly preferably not less than 200 mW/cm.sup.2,
for example, as a measurement value by the illuminance meter
(Ultraviolet intensity meter UM-10 produced by Konica Minolta,
Light-Receptor UM-360 [Peak sensitivity wavelength: 365 nm,
measured wavelength range: 310 to 400 nm]). Incidentally, an
irradiation intensity less than 100 mW/cm.sup.2 takes a long time
to remove the surface condition 10 provided with water
repellency.
[0082] Additionally, in the case of removing the surface condition
10 provided with water repellency by light irradiation, it is
particularly preferable to generate active oxygen in parallel with
decomposing components of the surface condition 10 provided with
water repellency by ultraviolet rays and then to induce
oxidation-volatilization of the components of the surface condition
10 provided with water repellency by the active oxygen, since a
treating time is to be saved thereby. As the light source therefor,
the low-pressure mercury light or the excimer lamp is used.
[0083] In the case of heating the silicon wafer, heating of the
silicon wafer is conducted at 400 to 700.degree. C., preferably at
500 to 700.degree. C. It is preferable to keep the heating time
from 1 to 60 min, preferably from 10 to 30 min. Additionally, this
step may be conducted in combination with ozone exposure, plasma
irradiation, corona discharge or the like.
EXAMPLES
[0084] To make a silicon wafer have a surface with a finely uneven
pattern and to substitute a cleaning liquid retained in recessed
portions with another cleaning liquid are already-established
techniques, as discussed in conventionally known literatures and
the like. In the present invention, therefore, evaluations of
water-repellent cleaning liquid were mainly performed.
Additionally, a pattern collapse greatly depends on the contact
angle of the cleaning liquid to the surface of the silicon wafer or
the contact angle of liquid drop, and the surface tension of the
cleaning liquid, as clearly represented by the equation discussed
as the background of the technique
P=2.times..gamma..times.cos .theta./S (.gamma.: Surface tension,
.theta.: Contact angle, S: Pattern width).
In a case of a cleaning liquid retained in the recessed portions 4
of the uneven pattern 2, the contact angle of liquid drop and the
capillary force which is considerable as an equivalent of the
pattern collapse are in correlation with each other, so that the
capillary force may be derived from the equation and the evaluation
of the contact angle of liquid drop on the surface condition 10
provided with water repellency. Incidentally, in Examples, a
representative of a water-based cleaning agent was used, i.e.,
water.
[0085] However, in a case where the silicon wafer has a finely
uneven pattern at its surface, the pattern is significantly fine.
Therefore it is not possible to exactly evaluate the water
repellency of the water repellency-provided surface condition 10
itself.
[0086] Evaluation of the contact angle of waterdrop for evaluating
the water repellency is conducted by dropping several microliters
of waterdrop on a surface of a sample (substrate) and then by
measuring an angle formed between the waterdrop and the substrate
surface, as discussed in JIS R 3257 (Testing method of wettability
of glass substrate surface). However, in the case of the silicon
wafer having a pattern, the contact angle is enormously large. This
is because Wenzel's effect or Cassie's effect is caused. That is
because an apparent contact angle of the waterdrop is increased
under the influence of a surface shape (roughness) of the substrate
upon the contact angle.
[0087] In view of this, in the present invention, various
evaluations are performed by providing the water-repellent cleaning
liquid to an even silicon wafer so as to bring about a surface
condition provided with water-repellency and then regarding the
surface condition as a water repellency-provided surface condition
10 of the silicon wafer at which surface an uneven pattern 2 is
formed.
[0088] Details will be discussed below. Hereinafter, there will be
discussed an evaluation method for the silicon wafer provided with
the water-repellent cleaning liquid, the preparation of the
water-repellent cleaning liquid, and results of evaluations after
providing the water-repellent cleaning liquid to the silicon
wafer.
[0089] [Evaluation Method for Silicon Wafer to which
Water-Repellent Cleaning Liquid is Provided]
[0090] As an evaluation method for the silicon wafer provided with
the water-repellent cleaning liquid, the following evaluations (1)
to (4) were performed.
[0091] (1) Evaluation of Contact Angle of Surface Condition
Provided with Water Repellency by Water-Repellent Cleaning
Liquid
[0092] Pure water of about 2 microliters was dropped on a wafer
surface provided with water repellency, followed by measuring an
angle (contact angle) formed between the waterdrop and the wafer
surface by a contact angle meter (produced by Kyowa Interface
Science Co., Ltd.: CA-X Model). At this time, a water
repellency-provided surface condition having a contact angle within
a range of from 50 to 120 was determined as an acceptable one
(indicated in Tables with k).
[0093] (2) Evaluation of the Capillary Force
[0094] The capillary force (the absolute value of P) was obtained
by calculating P by using the following equation.
P=2.times..gamma..times.cos .theta./S
where .gamma. is a surface tension, .theta. is a contact angle, and
S is a pattern width. Incidentally, in a pattern having a line
width of 45 nm and an aspect ratio of 6, the pattern tends to
collapse in a case where the cleaning liquid used when the wafer
passes through an gas-liquid interface is water while difficult to
collapse in a case of 2-propanol. In a case where the pattern width
is 45 nm and the wafer surface is silicon oxide, when the cleaning
liquid is 2-propanol (Surface tension: 22 mN/m, Contact angle to
silicon oxide: 1.degree.), the capillary force is 0.98 MN/m.sup.2.
On the other hand, in a case of water having the largest surface
tension among liquids other than mercury (Surface tension: 72 mN/m,
Contact angle to silicon oxide: 2.5.degree.), the capillary force
is 3.2 MN/m.sup.2. Therefore, the objective was set to the
midpoint, 2.1 MN/m.sup.2. A capillary force of not greater than 2.1
MN/m.sup.2, at the time of retaining water, was determined as an
acceptable one (indicated in Tables with A).
[0095] (3) Removability for Surface Condition Provided with Water
Repellency by Water-Repellent Cleaning Liquid
[0096] Under the following conditions, the sample was irradiated
with UV rays from a metal halide lamp for 2 hours. Those having a
contact angle to waterdrop of not larger than 30.degree. after the
irradiation was determined as an acceptable one (indicated in
Tables with A). [0097] Lamp: M015-L312 produced by EYE GRAPHICS
CO., LTD. (Intensity: 1.5 kW) [0098] Illuminance: 128 mW/cm.sup.2
as a measurement value under the following conditions [0099]
Measuring Apparatus: Ultraviolet Intensity Meter (UM-10 produced by
Konica Minolta) [0100] Light-Receptor: UM-360 [0101]
(Light-Receptive Wavelength: 310 to 400 nm, Peak Wavelength: 365
nm) [0102] Measuring Mode: Irradiance Measurement
[0103] (4) Evaluation of Roughness of Silicon Wafer Surface after
Removing Water Repellency-Provided Surface Condition
[0104] The surface was observed by atomic force microscope
(produced by Seiko Instruments Inc.: SPI3700, 2.5 micrometer square
scan), thereby obtaining the centerline average surface roughness:
Ra (nm). Incidentally, Ra is one which is three-dimensionally
enlarged by applying the centerline average roughness defined by
JIS B 0601 to a measured surface and is calculated as "an average
value of absolute values of difference from standard surface to
designated surface" from the following equation. If the wafer has
an Ra value of not higher than 1 nm after removing the water
repellency-provided surface condition, the wafer surface was
considered not to be eroded and not to have a residue of the
water-repellent cleaning liquid thereon, so as to be determined as
an acceptable one (indicated in Tables with A).
Ra = 1 S 0 .intg. Y T Y B .intg. X L X R F ( X , Y ) - Z 0 X Y [
Mathematical Equation 1 ] ##EQU00001##
[0105] where X.sub.L and X.sub.R and Y.sub.B and Y.sub.T represent
a measuring range in the X coordinate and the Y coordinate,
respectively. S.sub.0 is an area on the assumption that a measured
surface is ideally flat, and is a value obtained by
(X.sub.R-X.sub.L).times.(Y.sub.B-Y.sub.T). Additionally, F(X,Y)
represents a height at a measured point (X,Y) while Z.sub.0
represents an average height within the measured surface.
[0106] The following Examples 1 to 44 exemplifies a first cleaning
agent while the following Comparative Examples 1 and 2 are opposed
to the first cleaning agent. Results of these are shown in Table 1
and Table 2.
Example 1
(1) Preparation of Water-Repellent Cleaning Liquid
[0107] A mixture of 3 g of trimethylchlorosilane
[(CH.sub.3).sub.3SiCl] serving as a water-repellent compound and 97
g of toluene serving as an organic solvent was stirred for 5 min
thereby obtaining a water-repellent cleaning liquid having a
concentration of the water-repellent compound (hereinafter referred
to as "a water-repellent compound concentration") of 3 mass %
relative to the total quantity of the water-repellent cleaning
liquid.
(2) Cleaning of Silicon Wafer
[0108] An even silicon wafer with a thermal oxide film (A Si wafer
having on its surface a thermal oxide film layer of 1 micrometer
thickness) was immersed in 1 mass % hydrofluoric acid aqueous
solution for 2 min, followed by being immersed in pure water for 1
min and then in acetone for 1 min.
(3) Surface Treatment of Silicon Wafer Surface by Water-Repellent
Cleaning Liquid
[0109] The water-repellent cleaning liquid prepared in the "(1)
Preparation of Water-Repellent Cleaning Liquid" was heated to
50.degree. C., followed by immersion in the cleaning liquid for 30
min. Thereafter, the silicon wafer was immersed in 2-propanol for 1
min and then immersed in pure water for 1 min. Finally, the silicon
wafer was taken out of the pure water and then an air was sprayed
thereon, thereby removing the pure water from the surface.
[0110] As a result of evaluating the obtained wafer in a manner as
discussed in the [Evaluation Method For Silicon Wafer To Which
Water-Repellent Cleaning Liquid Is Provided], one having had an
initial contact angle of smaller than 10.degree. before a surface
treatment changed to have a contact angle of 74.degree. after the
surface treatment, as shown in Table 1, thereby exhibiting a water
repellency-providing effect. Additionally, as a result of
calculating the capillary force at the time where water was
retained by using the equation discussed in the above-mentioned
"Evaluation of the capillary force", the capillary force was 0.9
MN/m.sup.2 and therefore the capillary force was small.
Additionally, the contact angle after UV irradiation was smaller
than 10.degree., so that removal of the water repellency-provided
surface condition was achieved. Furthermore, the Ra value of the
wafer after UV irradiation was smaller than 0.5 nm, with which it
was confirmed that the wafer was not eroded at the time of cleaning
and that the residue of the water-repellent cleaning liquid did not
remain after UV irradiation.
TABLE-US-00001 TABLE 1 Treatment of water-repellent Water-repellent
cleaning liquid cleaning liquid Water- before surface repellent
treatment compound Solvent used for Immersion Water-repellent
Organic concentration cleaning after Temperature Time compound
solvent [mass %] rinsing with water [.degree. C.] [min] Example 1
(CH.sub.3).sub.3SiCl Toluene 3 Acetone 50 30 Example 2
(CH.sub.3).sub.3SiCl Toluene 1 Acetone 50 30 Example 3
(CH.sub.3).sub.3SiNHSi(CH.sub.3).sub.3 Toluene 3 Acetone 50 30
Example 4 CF.sub.3CH.sub.2CH.sub.2SiCl.sub.3 Toluene 3 Acetone 50
30 Example 5 CF.sub.3CH.sub.2CH.sub.2Si(CH.sub.3)Cl.sub.2 Toluene 3
Acetone 50 30 Example 6
CF.sub.3CH.sub.2CH.sub.2Si(CH.sub.3).sub.2Cl Toluene 3 Acetone 50
30 Example 7 C.sub.18H.sub.37Si(CH.sub.3).sub.2Cl Toluene 3 Acetone
50 30 Example 8 (CH.sub.3).sub.3SiCl +
CF.sub.3CH.sub.2CH.sub.2Si(CH.sub.3).sub.2Cl Toluene 3 Acetone 50
30 Example 9 (CH.sub.3).sub.3SiCl HFE-7100 3 Acetone 50 30 Example
10 (CH.sub.3).sub.3SiCl ZEORORA-H 3 Acetone 50 30 Example 11
(CH.sub.3).sub.3SiCl DCTFP 3 Acetone 50 30 Example 12
(CH.sub.3).sub.3SiCl CTFP 3 Acetone 50 30 Example 13
(CH.sub.3).sub.3SiCl HFE-7100 3 Acetone 50 30 Example 14
(CH.sub.3).sub.3SiCl DCTFP 3 Acetone 50 30 Example 15
(CH.sub.3).sub.3SiCl HFE-7100 3 Acetone 50 30 Example 16
(CH.sub.3).sub.3SiCl DCTFP 3 Acetone 50 30 Example 17
(CH.sub.3).sub.3SiCl DCTFP 3 Acetone 50 30 Example 18
(CH.sub.3).sub.3SiCl DCTFP 3 Acetone 50 30 Example 19
(CH.sub.3).sub.3SiCl DCTFP 3 Acetone 50 30 Example 20
(CH.sub.3).sub.3SiCl HFE-7100 3 Acetone 50 30 Example 21
(CH.sub.3).sub.3SiCl DCTFP 3 Acetone 50 30 Example 22
(CH.sub.3).sub.3SiCl Toluene 3 iPA 50 30 Example 23
(CH.sub.3).sub.3SiCl HFE-7100 3 iPA 50 30 Example 24
(CH.sub.3).sub.3SiCl DCTFP 3 iPA 50 30 Example 25
(CH.sub.3).sub.3SiCl PGMEA 3 iPA 50 30 Example 26
(CH.sub.3).sub.3SiCl HFE- 3 iPA 50 30 7100 + PGMEA Example 27
(CH.sub.3).sub.3SiCl HFE-7100 3 iPA 50 30 Example 28
(CH.sub.3).sub.3SiCl DCTFP 3 iPA 50 30 Example 29
(CH.sub.3).sub.3SiCl HFE-7100 3 iPA 50 30 Example 30
(CH.sub.3).sub.3SiCl DCTFP 3 iPA 50 30 Evaluation results
Removability of water- Treatment of water-repellent cleaning
Contact Capillary repellent liquid after surface treatment Initial
angle after force surface Cleaning Cleaning contact surface
[MN/m.sup.2] condition Surface with with angle treatment
<calculated (contact roughness Drying solvent water Drying
[.degree.] [.degree.] value> angle [.degree.]) (Ra [nm]) Example
1 Not done Done Done Done <10 A (74) A (0.9) A (<10) A
(<0.5) Example 2 Not done Done Done Done <10 A (68) A (1.2) A
(<10) A (<0.5) Example 3 Not done Done Done Done <10 A
(55) A (1.8) A (<10) A (<0.5) Example 4 Not done Done Done
Done <10 A (86) A (0.2) A (<10) A (<0.5) Example 5 Not
done Done Done Done <10 A (84) A (0.3) A (<10) A (<0.5)
Example 6 Not done Done Done Done <10 A (70) A (1.1) A (<10)
A (<0.5) Example 7 Not done Done Done Done <10 A (88) A (0.1)
A (<10) A (<0.5) Example 8 Not done Done Done Done <10 A
(76) A (0.8) A (<10) A (<0.5) Example 9 Not done Done Done
Done <10 A (74) A (0.9) A (<10) A (<0.5) Example 10 Not
done Done Done Done <10 A (78) A (0.7) A (<10) A (<0.5)
Example 11 Not done Done Done Done <10 A (72) A (1.0) A (<10)
A (<0.5) Example 12 Not done Done Done Done <10 A (74) A
(0.9) A (<10) A (<0.5) Example 13 Not done Done Not done Done
<10 A (72) A (1.0) A (<10) A (<0.5) Example 14 Not done
Done Not done Done <10 A (70) A (1.1) A (<10) A (<0.5)
Example 15 Not done Not done Done Done <10 A (74) A (0.9) A
(<10) A (<0.5) Example 16 Not done Not done Done Done <10
A (72) A (1.0) A (<10) A (<0.5) Example 17 Done Done Done
Done <10 A (72) A (1.0) A (<10) A (<0.5) Example 18 Done
Done Not done Done <10 A (70) A (1.1) A (<10) A (<0.5)
Example 19 Done Not done Done Done <10 A (72) A (1.0) A (<10)
A (<0.5) Example 20 Done Not done Not done Not done <10 A
(74) A (0.9) A (<10) A (<0.5) Example 21 Done Not done Not
done Not done <10 A (72) A (1.0) A (<10) A (<0.5) Example
22 Not done Done Done Done <10 A (72) A (1.0) A (<10) A
(<0.5) Example 23 Not done Done Done Done <10 A (72) A (1.0)
A (<10) A (<0.5) Example 24 Not done Done Done Done <10 A
(70) A (1.1) A (<10) A (<0.5) Example 25 Not done Done Done
Done <10 A (66) A (1.3) A (<10) A (<0.5) Example 26 Not
done Done Done Done <10 A (76) A (0.8) A (<10) A (<0.5)
Example 27 Not done Done Not done Done <10 A (70) A (1.1) A
(<10) A (<0.5) Example 28 Not done Done Not done Done <10
A (70) A (1.1) A (<10) A (<0.5) Example 29 Done Not done Not
done Not done <10 A (72) A (1.0) A (<10) A (<0.5) Example
30 Done Not done Not done Not done <10 A (72) A (1.0) A (<10)
A (<0.5)
TABLE-US-00002 TABLE 2 Treatment of water- repellent cleaning
liquid before surface Water-repellent cleaning liquid treatment
Treatment of water-repellent cleaning liquid Water-repellent
Solvent used after surface treatment compound for cleaning
Immersion Cleaning Water-repellent Organic concentration after
rinsing Temperature Time with Cleaning compound solvent [mass %]
with water [.degree. C.] [min] Drying solvent with water Drying
Example 31 (CH.sub.3).sub.3SiCl Toluene 3 iPA, Toluene 50 30 Not
done Done Done Done Example 32 (CH.sub.3).sub.3SiCl HFE-7100 3 iPA,
50 30 Not done Done Done Done HFE-7100 Example 33
(CH.sub.3).sub.3SiCl Toluene 3 None 50 30 Not done Done Done Done
Example 34 (CH.sub.3).sub.3SiCl HFE-7100 3 None 50 30 Not done Done
Done Done Example 35 C.sub.2H.sub.5Si(CH.sub.3).sub.2Cl HFE-7100 3
iPA 50 30 Not done Done Done Done Example 36
C.sub.3H.sub.7Si(CH.sub.3).sub.2Cl HFE-7100 3 iPA 50 30 Not done
Done Done Done Example 37 (CH.sub.3).sub.3SiNHSi(CH.sub.3).sub.3
Toluene 5 Acetone 50 30 Not done Done Done Done Example 38
(CH.sub.3).sub.3SiNHSi(CH.sub.3).sub.3 Toluene 5 Acetone 50 30 Not
done Done Done Done Example 39
(CH.sub.3).sub.3SiNHSi(CH.sub.3).sub.3 HFE-7100 + 5 iPA 50 30 Not
done Done Done Done PGMEA Example 40
(CH.sub.3).sub.3SiNHSi(CH.sub.3).sub.3 HFE-7100 + 5 iPA 50 30 Not
done Done Done Done PGMEA Example 41
(CH.sub.3).sub.3SiNHSi(CH.sub.3).sub.3 PGMEA 5 iPA 50 30 Not done
Done Done Done Example 42 (CH.sub.3).sub.3SiNHSi(CH.sub.3).sub.3
PGMEA 5 iPA 50 30 Not done Done Done Done Example 43
(CH.sub.3).sub.3SiNHSi(CH.sub.3).sub.3 PGMEA 5 iPA 50 30 Not done
Done Not done Done Example 44
(CH.sub.3).sub.3SiNHSi(CH.sub.3).sub.3 PGMEA 5 iPA 50 30 Not done
Done Not done Done Comparative Not treated -- -- Acetone -- -- Not
done Done Done Done Example 1 Comparative Hydrolysate of iPA 3
Acetone 50 30 Not done Done Done Done Example 2
(CH.sub.3).sub.3SiCl Evaluation results Removability of water-
Contact Capillary repellent Initial angle after force surface
contact surface [MN/m.sup.2] condition Surface angle treatment
<calculated (contact roughness [.degree.] [.degree.] value>
angle [.degree.]) (Ra [nm]) Example 31 <10 A (74) A (0.9) A
(<10) A (<0.5) Example 32 <10 A (74) A (0.9) A (<10) A
(<0.5) Example 33 <10 A (70) A (1.1) A (<10) A (<0.5)
Example 34 <10 A (70) A (1.1) A (<10) A (<0.5) Example 35
<10 A (76) A (0.8) A (<10) A (<0.5) Example 36 <10 A
(80) A (0.6) A (<10) A (<0.5) Example 37 <10 A (86) A
(0.2) A (<10) A (<0.5) Example 38 <10 A (86) A (0.2) A
(<10) A (<0.5) Example 39 <10 A (86) A (0.2) A (<10) A
(<0.5) Example 40 <10 A (86) A (0.2) A (<10) A (<0.5)
Example 41 <10 A (84) A (0.3) A (<10) A (<0.5) Example 42
<10 A (84) A (0.3) A (<10) A (<0.5) Example 43 <10 A
(84) A (0.3) A (<10) A (<0.5) Example 44 <10 A (84) A
(0.3) A (<10) A (<0.5) Comparative <10 B (3) B (3.2) -- A
(<0.5) Example 1 Comparative <10 B (20) B (2.7) -- -- Example
2
Example 2
[0111] The manner was all the same as Example 1 with the exception
that the water-repellent compound concentration was set to 1 mass
%. As shown in the evaluation result of Table 1, the contact angle
after the surface treatment was 68.degree. and therefore the water
repellency-providing effect was exhibited. Additionally, the
capillary force at the time where water was retained was 1.2
MN/m.sup.2 and therefore the capillary force was small.
Additionally, the contact angle after UV irradiation was smaller
than 10.degree., so that removal of the water repellency-provided
surface condition was achieved. Furthermore, the Ra value of the
wafer after UV irradiation was smaller than 0.5 nm, with which it
was confirmed that the wafer was not eroded at the time of cleaning
and that the residue of the water-repellent cleaning liquid did not
remain after UV irradiation.
Example 3
[0112] The manner was all the same as Example 1 with the exception
that hexamethyldisilazane [(CH.sub.3).sub.3SiNHSi(CH.sub.3).sub.3]
was used as the water-repellent compound. As shown in the
evaluation result of Table 1, the contact angle after the surface
treatment was 55.degree. and therefore the water
repellency-providing effect was exhibited. Additionally, the
capillary force at the time where water was retained was 1.8
MN/m.sup.2 and therefore the capillary force was small.
Additionally, the contact angle after UV irradiation was smaller
than 10.degree., so that removal of the water repellency-provided
surface condition was achieved. Furthermore, the Ra value of the
wafer after UV irradiation was smaller than 0.5 nm, with which it
was confirmed that the wafer was not eroded at the time of cleaning
and that the residue of the water-repellent cleaning liquid did not
remain after UV irradiation.
Example 4
[0113] The manner was all the same as Example 1 with the exception
that (trifluoropropyl)trichlorosilane
[CF.sub.3CH.sub.2CH.sub.2SiCl.sub.3] was used as the
water-repellent compound. As shown in the evaluation result of
Table 1, the contact angle after the surface treatment was
86.degree. and therefore the water repellency-providing effect was
excellently exhibited. Additionally, the capillary force at the
time where water was retained was 0.2 MN/m.sup.2 and therefore the
capillary force was small. Additionally, the contact angle after UV
irradiation was smaller than 10.degree., so that removal of the
water repellency-provided surface condition was achieved.
Furthermore, the Ra value of the wafer after UV irradiation was
smaller than 0.5 nm, with which it was confirmed that the wafer was
not eroded at the time of cleaning and that the residue of the
water-repellent cleaning liquid did not remain after UV
irradiation.
Example 5
[0114] The manner was all the same as Example 1 with the exception
that (trifluoropropyl)methyldichlorosilane
[CF.sub.3CH.sub.2CH.sub.2Si(CH.sub.3)Cl.sub.2] was used as the
water-repellent compound. As shown in the evaluation result of
Table 1, the contact angle after the surface treatment was
84.degree. and therefore the water repellency-providing effect was
excellently exhibited. Additionally, the capillary force at the
time where water was retained was 0.3 MN/m.sup.2 and therefore the
capillary force was small. Additionally, the contact angle after UV
irradiation was smaller than 10.degree., so that removal of the
water repellency-provided surface condition was achieved.
Furthermore, the Ra value of the wafer after UV irradiation was
smaller than 0.5 nm, with which it was confirmed that the wafer was
not eroded at the time of cleaning and that the residue of the
water-repellent cleaning liquid did not remain after UV
irradiation.
Example 6
[0115] The manner was all the same as Example 1 with the exception
that (trifluoropropyl)dimethylchlorosilane
[CF.sub.3CH.sub.2CH.sub.2Si(CH.sub.3).sub.2Cl] was used as the
water-repellent compound. As shown in the evaluation result of
Table 1, the contact angle after the surface treatment was
70.degree. and therefore the water repellency-providing effect was
exhibited. Additionally, the capillary force at the time where
water was retained was 1.1 MN/m.sup.2 and therefore the capillary
force was small. Additionally, the contact angle after UV
irradiation was smaller than 10.degree., so that removal of the
water repellency-provided surface condition was achieved.
Furthermore, the Ra value of the wafer after UV irradiation was
smaller than 0.5 nm, with which it was confirmed that the wafer was
not eroded at the time of cleaning and that the residue of the
water-repellent cleaning liquid did not remain after UV
irradiation.
Example 7
[0116] The manner was all the same as Example 1 with the exception
that octadecyldimethylchlorosilane
[C.sub.18H.sub.37Si(CH.sub.3).sub.2Cl] was used as the
water-repellent compound. As shown in the evaluation result of
Table 1, the contact angle after the surface treatment was
88.degree. and therefore the water repellency-providing effect was
excellently exhibited. Additionally, the capillary force at the
time where water was retained was 0.1 MN/m.sup.2 and therefore the
capillary force was small. Additionally, the contact angle after UV
irradiation was smaller than 10.degree., so that removal of the
water repellency-provided surface condition was achieved.
Furthermore, the Ra value of the wafer after UV irradiation was
smaller than 0.5 nm, with which it was confirmed that the wafer was
not eroded at the time of cleaning and that the residue of the
water-repellent cleaning liquid did not remain after UV
irradiation.
Example 8
[0117] The manner was all the same as Example 1 with the exception
that trimethylchlorosilane [(CH.sub.3).sub.3SiCl] and
trifluoropropyldimethylchlorosilane
[CF.sub.3CH.sub.2CH.sub.2Si(CH.sub.3).sub.2Cl] were used as the
water-repellent compound at a mass ratio of 50:50 and that the
total concentration of the water-repellent compound was 3 mass %.
As shown in the evaluation result of Table 1, the contact angle
after the surface treatment was 76.degree. and therefore the water
repellency-providing effect was exhibited. Additionally, the
capillary force at the time where water was retained was 0.8
MN/m.sup.2 and therefore the capillary force was small.
Additionally, the contact angle after UV irradiation was smaller
than 10.degree., so that removal of the water repellency-provided
surface condition was achieved. Furthermore, the Ra value of the
wafer after UV irradiation was smaller than 0.5 nm, with which it
was confirmed that the wafer was not eroded at the time of cleaning
and that the residue of the water-repellent cleaning liquid did not
remain after UV irradiation.
Example 9
[0118] The manner was all the same as Example 1 with the exception
that hydrofluoroether (HFE-7100 produced by 3M Limited) was used as
the organic solvent contained in the water-repellent cleaning
liquid. As shown in the evaluation result of Table 1, the contact
angle after the surface treatment was 74.degree. and therefore the
water repellency-providing effect was exhibited. Additionally, the
capillary force at the time where water was retained was 0.9
MN/m.sup.2 and therefore the capillary force was small.
Additionally, the contact angle after UV irradiation was smaller
than 10.degree., so that removal of the water repellency-provided
surface condition was achieved. Furthermore, the Ra value of the
wafer after UV irradiation was smaller than 0.5 nm, with which it
was confirmed that the wafer was not eroded at the time of cleaning
and that the residue of the water-repellent cleaning liquid did not
remain after UV irradiation.
Example 10
[0119] The manner was all the same as Example 1 with the exception
that a halogen-containing solvent (ZEORORA-H produced by ZEON
CORPORATION: 1,1,2,2,3,3,4-heptafluorocyclopentane) was used as the
organic solvent contained in the water-repellent cleaning liquid.
As shown in the evaluation result of Table 1, the contact angle
after the surface treatment was 78.degree. and therefore the water
repellency-providing effect was exhibited. Additionally, the
capillary force at the time where water was retained was 0.7
MN/m.sup.2 and therefore the capillary force was small.
Additionally, the contact angle after UV irradiation was smaller
than 10.degree., so that removal of the water repellency-provided
surface condition was achieved. Furthermore, the Ra value of the
wafer after UV irradiation was smaller than 0.5 nm, with which it
was confirmed that the wafer was not eroded at the time of cleaning
and that the residue of the water-repellent cleaning liquid did not
remain after UV irradiation.
Example 11
[0120] The manner was all the same as Example 1 with the exception
that cis-1,2-dichloro-3,3,3-trifluoropropene (DCTFP) was used as
the organic solvent contained in the water-repellent cleaning
liquid. As shown in the evaluation result of Table 1, the contact
angle after the surface treatment was 72.degree. and therefore the
water repellency-providing effect was exhibited. Additionally, the
capillary force at the time where water was retained was 1.0
MN/m.sup.2 and therefore the capillary force was small.
Additionally, the contact angle after UV irradiation was smaller
than 10.degree., so that removal of the water repellency-provided
surface condition was achieved. Furthermore, the Ra value of the
wafer after UV irradiation was smaller than 0.5 nm, with which it
was confirmed that the wafer was not eroded at the time of cleaning
and that the residue of the water-repellent cleaning liquid did not
remain after UV irradiation.
Example 12
[0121] The manner was all the same as Example 1 with the exception
that 1-chloro-3,3,3-trifluoropropene (CTFP) was used as the organic
solvent contained in the water-repellent cleaning liquid. As shown
in the evaluation result of Table 1, the contact angle after the
surface treatment was 74.degree. and therefore the water
repellency-providing effect was exhibited. Additionally, the
capillary force at the time where water was retained was 0.9
MN/m.sup.2 and therefore the capillary force was small.
Additionally, the contact angle after UV irradiation was smaller
than 10.degree., so that removal of the water repellency-provided
surface condition was achieved. Furthermore, the Ra value of the
wafer after UV irradiation was smaller than 0.5 nm, with which it
was confirmed that the wafer was not eroded at the time of cleaning
and that the residue of the water-repellent cleaning liquid did not
remain after UV irradiation.
Example 13
[0122] The manner was all the same as Example 9 with the exception
that, at the above-mentioned "(3) Surface Treatment of Silicon
Wafer Surface by Water-Repellent Cleaning Liquid" the silicon wafer
was immersed in 2-propanol for 1 min after being immersed in the
water-repellent cleaning liquid and that the silicon wafer was
finally taken out of 2-propanol, followed by spraying air thereon
to remove 2-propanol from the surface thereby obtaining a wafer
provided with a water repellency-provided surface condition. As
shown in the evaluation result of Table 1, the contact angle after
the surface treatment was 72.degree. and therefore the water
repellency-providing effect was exhibited. Additionally, the
capillary force at the time where water was retained was 1.0
MN/m.sup.2 and therefore the capillary force was small.
Additionally, the contact angle after UV irradiation was smaller
than 10.degree., so that removal of the water repellency-provided
surface condition was achieved. Furthermore, the Ra value of the
wafer after UV irradiation was smaller than 0.5 nm, with which it
was confirmed that the wafer was not eroded at the time of cleaning
and that the residue of the water-repellent cleaning liquid did not
remain after UV irradiation.
Example 14
[0123] The manner was all the same as Example 13 with the exception
that DCTFP was used as the organic solvent contained in the
water-repellent cleaning liquid. As shown in the evaluation result
of Table 1, the contact angle after the surface treatment was
70.degree. and therefore the water repellency-providing effect was
exhibited. Additionally, the capillary force at the time where
water was retained was 1.1 MN/m.sup.2 and therefore the capillary
force was small. Additionally, the contact angle after UV
irradiation was smaller than 10.degree., so that removal of the
water repellency-provided surface condition was achieved.
Furthermore, the Ra value of the wafer after UV irradiation was
smaller than 0.5 nm, with which it was confirmed that the wafer was
not eroded at the time of cleaning and that the residue of the
water-repellent cleaning liquid did not remain after UV
irradiation.
Example 15
[0124] The manner was all the same as Example 9 with the exception
that, at the above-mentioned "(3) Surface Treatment of Silicon
Wafer Surface by Water-Repellent Cleaning Liquid", the silicon
wafer was immersed in pure water for 1 min after being immersed in
the water-repellent cleaning liquid and that the silicon wafer was
finally taken out of the pure water, followed by spraying air
thereon thereby obtaining a wafer which is in a water
repellency-provided surface condition. As shown in the evaluation
result of Table 1, the contact angle after the surface treatment
was 74.degree. and therefore the water repellency-providing effect
was exhibited. Additionally, the capillary force at the time where
water was retained was 0.9 MN/m.sup.2 and therefore the capillary
force was small. Additionally, the contact angle after UV
irradiation was smaller than 10.degree., so that removal of the
water repellency-provided surface condition was achieved.
Furthermore, the Ra value of the wafer after UV irradiation was
smaller than 0.5 nm, with which it was confirmed that the wafer was
not eroded at the time of cleaning and that the residue of the
water-repellent cleaning liquid did not remain after UV
irradiation.
Example 16
[0125] The manner was all the same as Example 15 with the exception
that DCTFP was used as the organic solvent contained in the
water-repellent cleaning liquid. As shown in the evaluation result
of Table 1, the contact angle after the surface treatment was
72.degree. and therefore the water repellency-providing effect was
exhibited. Additionally, the capillary force at the time where
water was retained was 1.0 MN/m.sup.2 and therefore the capillary
force was small. Additionally, the contact angle after UV
irradiation was smaller than 10.degree., so that removal of the
water repellency-provided surface condition was achieved.
Furthermore, the Ra value of the wafer after UV irradiation was
smaller than 0.5 nm, with which it was confirmed that the wafer was
not eroded at the time of cleaning and that the residue of the
water-repellent cleaning liquid did not remain after UV
irradiation.
Example 17
[0126] The manner was all the same as Example 11 with the exception
that, at the above-mentioned "(3) Surface Treatment of Silicon
Wafer Surface by Water-Repellent Cleaning Liquid", the silicon
wafer was immersed in the water-repellent cleaning liquid, followed
by spraying air thereon thereby removing the water-repellent
cleaning liquid from its surface, and subsequently that the silicon
wafer was immersed in 2-propanol for 1 min and pure water for 1 min
and finally taken out of the pure water, followed by spraying air
thereon to remove the pure water from the surface thereby obtaining
a wafer which is in a water repellency-provided surface condition.
As shown in the evaluation result of Table 1, the contact angle
after the surface treatment was 72.degree. and therefore the water
repellency-providing effect was exhibited. Additionally, the
capillary force at the time where water was retained was 1.0
MN/m.sup.2 and therefore the capillary force was small.
Additionally, the contact angle after UV irradiation was smaller
than 10.degree., so that removal of the water repellency-provided
surface condition was achieved. Furthermore, the Ra value of the
wafer after UV irradiation was smaller than 0.5 nm, with which it
was confirmed that the wafer was not eroded at the time of cleaning
and that the residue of the water-repellent cleaning liquid did not
remain after UV irradiation.
Example 18
[0127] The manner was all the same as Example 11 with the exception
that, at the above-mentioned "(3) Surface Treatment of Silicon
Wafer Surface by Water-Repellent Cleaning Liquid", the silicon
wafer was immersed in the water-repellent cleaning liquid, followed
by spraying air thereon thereby removing the water-repellent
cleaning liquid from its surface, and subsequently that the silicon
wafer was immersed in 2-propanol for 1 min and finally taken out of
2-propanol, followed by spraying air thereon to remove 2-propanol
from the surface thereby obtaining a wafer which is in a water
repellency-provided surface condition. As shown in the evaluation
result of Table 1, the contact angle after the surface treatment
was 70.degree. and therefore the water repellency-providing effect
was exhibited. Additionally, the capillary force at the time where
water was retained was 1.1 MN/m.sup.2 and therefore the capillary
force was small. Additionally, the contact angle after UV
irradiation was smaller than 10.degree., so that removal of the
water repellency-provided surface condition was achieved.
Furthermore, the Ra value of the wafer after UV irradiation was
smaller than 0.5 nm, with which it was confirmed that the wafer was
not eroded at the time of cleaning and that the residue of the
water-repellent cleaning liquid did not remain after UV
irradiation.
Example 19
[0128] The manner was all the same as Example 11 with the exception
that, at the above-mentioned "(3) Surface Treatment of Silicon
Wafer Surface by Water-Repellent Cleaning Liquid", the silicon
wafer was immersed in the water-repellent cleaning liquid, followed
by spraying air thereon to remove the water-repellent cleaning
liquid from its surface, and subsequently that the silicon wafer
was immersed in pure water for 1 min and finally taken out of the
pure water, followed by spraying air thereon to remove the pure
water from the surface thereby obtaining a wafer which is in a
water repellency-provided surface condition. As shown in the
evaluation result of Table 1, the contact angle after the surface
treatment was 72.degree. and therefore the water
repellency-providing effect was exhibited. Additionally, the
capillary force at the time where water was retained was 1.0
MN/m.sup.2 and therefore the capillary force was small.
Additionally, the contact angle after UV irradiation was smaller
than 10.degree., so that removal of the water repellency-provided
surface condition was achieved. Furthermore, the Ra value of the
wafer after UV irradiation was smaller than 0.5 nm, with which it
was confirmed that the wafer was not eroded at the time of cleaning
and that the residue of the water-repellent cleaning liquid did not
remain after UV irradiation.
Example 20
[0129] The manner was all the same as Example 9 with the exception
that, at the above-mentioned "(3) Surface Treatment of Silicon
Wafer Surface by Water-Repellent Cleaning Liquid", air was sprayed
on the silicon wafer after taking the silicon wafer out of the
water-repellent cleaning liquid thereby obtaining a wafer which is
in a water repellency-provided surface condition. As shown in the
evaluation result of Table 1, the contact angle after the surface
treatment was 74.degree. and therefore the water
repellency-providing effect was exhibited. Additionally, the
capillary force at the time where water was retained was 0.9
MN/m.sup.2 and therefore the capillary force was small.
Additionally, the contact angle after UV irradiation was smaller
than 10.degree., so that removal of the water repellency-provided
surface condition was achieved. Furthermore, the Ra value of the
wafer after UV irradiation was smaller than 0.5 nm, with which it
was confirmed that the wafer was not eroded at the time of cleaning
and that the residue of the water-repellent cleaning liquid did not
remain after UV irradiation.
Example 21
[0130] The manner was all the same as Example 20 with the exception
that cis-1,2-dichloro-3,3,3-trifluoropropene (DCTFP) was used as
the organic solvent contained in the water-repellent cleaning
liquid. As shown in the evaluation result of Table 1, the contact
angle after the surface treatment was 72.degree. and therefore the
water repellency-providing effect was exhibited. Additionally, the
capillary force at the time where water was retained was 1.0
MN/m.sup.2 and therefore the capillary force was small.
Additionally, the contact angle after UV irradiation was smaller
than 10.degree., so that removal of the water repellency-provided
surface condition was achieved. Furthermore, the Ra value of the
wafer after UV irradiation was smaller than 0.5 nm, with which it
was confirmed that the wafer was not eroded at the time of cleaning
and that the residue of the water-repellent cleaning liquid did not
remain after UV irradiation.
Example 22
[0131] The manner was all the same as Example 1 with the exception
that the silicon wafer was immersed in pure water for 1 min and
immersed in 2-propanol (iPA) for 1 min after being immersed in
hydrofluoric acid aqueous solution at the above-mentioned "(2)
Cleaning of Silicon Wafer". As shown in the evaluation result of
Table 1, the contact angle after the surface treatment was
72.degree. and therefore the water repellency-providing effect was
exhibited. Additionally, the capillary force at the time where
water was retained was 1.0 MN/m.sup.2 and therefore the capillary
force was small. Additionally, the contact angle after UV
irradiation was smaller than 10.degree., so that removal of the
water repellency-provided surface condition was achieved.
Furthermore, the Ra value of the wafer after UV irradiation was
smaller than 0.5 nm, with which it was confirmed that the wafer was
not eroded at the time of cleaning and that the residue of the
water-repellent cleaning liquid did not remain after UV
irradiation.
Example 23
[0132] The manner was all the same as Example 9 with the exception
that the silicon wafer was immersed in pure water for 1 min and
immersed in 2-propanol (iPA) for 1 min after being immersed in
hydrofluoric acid aqueous solution at the above-mentioned "(2)
Cleaning of Silicon Wafer". As shown in the evaluation result of
Table 1, the contact angle after the surface treatment was
72.degree. and therefore the water repellency-providing effect was
exhibited. Additionally, the capillary force at the time where
water was retained was 1.0 MN/m.sup.2 and therefore the capillary
force was small. Additionally, the contact angle after UV
irradiation was smaller than 10.degree., so that removal of the
water repellency-provided surface condition was achieved.
Furthermore, the Ra value of the wafer after UV irradiation was
smaller than 0.5 nm, with which it was confirmed that the wafer was
not eroded at the time of cleaning and that the residue of the
water-repellent cleaning liquid did not remain after UV
irradiation.
Example 24
[0133] The manner was all the same as Example 11 with the exception
that the silicon wafer was immersed in pure water for 1 min and
immersed in 2-propanol (iPA) for 1 min after being immersed in
hydrofluoric acid aqueous solution at the above-mentioned "(2)
Cleaning of Silicon Wafer". As shown in the evaluation result of
Table 1, the contact angle after the surface treatment was
70.degree. and therefore the water repellency-providing effect was
exhibited. Additionally, the capillary force at the time where
water was retained was 1.1 MN/m.sup.2 and therefore the capillary
force was small. Additionally, the contact angle after UV
irradiation was smaller than 10.degree., so that removal of the
water repellency-provided surface condition was achieved.
Furthermore, the Ra value of the wafer after UV irradiation was
smaller than 0.5 nm, with which it was confirmed that the wafer was
not eroded at the time of cleaning and that the residue of the
water-repellent cleaning liquid did not remain after UV
irradiation.
Example 25
[0134] The manner was all the same as Example 24 with the exception
that PGMEA was used as the organic solvent contained in the
water-repellent cleaning liquid. As shown in the evaluation result
of Table 1, the contact angle after the surface treatment was
66.degree. and therefore the water repellency-providing effect was
exhibited. Additionally, the capillary force at the time where
water was retained was 1.3 MN/m.sup.2 and therefore the capillary
force was small. Additionally, the contact angle after UV
irradiation was smaller than 10.degree., so that removal of the
water repellency-provided surface condition was achieved.
Furthermore, the Ra value of the wafer after UV irradiation was
smaller than 0.5 nm, with which it was confirmed that the wafer was
not eroded at the time of cleaning and that the residue of the
water-repellent cleaning liquid did not remain after UV
irradiation.
Example 26
[0135] The manner was all the same as Example 24 with the exception
that HFE-7100 and PGMEA were used as organic solvent in the
water-repellent cleaning liquid at a mass ratio of 97:3. As shown
in the evaluation result of Table 1, the contact angle after the
surface treatment was 76.degree. and therefore the water
repellency-providing effect was exhibited. Additionally, the
capillary force at the time where water was retained was 0.8
MN/m.sup.2 and therefore the capillary force was small.
Additionally, the contact angle after UV irradiation was smaller
than 10.degree., so that removal of the water repellency-provided
surface condition was achieved. Furthermore, the Ra value of the
wafer after UV irradiation was smaller than 0.5 nm, with which it
was confirmed that the wafer was not eroded at the time of cleaning
and that the residue of the water-repellent cleaning liquid did not
remain after UV irradiation.
Example 27
[0136] The manner was all the same as Example 13 with the exception
that the silicon wafer was immersed in pure water for 1 min and
immersed in 2-propanol (iPA) for 1 min after being immersed in
hydrofluoric acid aqueous solution at the above-mentioned "(2)
Cleaning of Silicon Wafer". As shown in the evaluation result of
Table 1, the contact angle after the surface treatment was
70.degree. and therefore the water repellency-providing effect was
exhibited. Additionally, the capillary force at the time where
water was retained was 1.1 MN/m.sup.2 and therefore the capillary
force was small. Additionally, the contact angle after UV
irradiation was smaller than 10.degree., so that removal of the
water repellency-provided surface condition was achieved.
Furthermore, the Ra value of the wafer after UV irradiation was
smaller than 0.5 nm, with which it was confirmed that the wafer was
not eroded at the time of cleaning and that the residue of the
water-repellent cleaning liquid did not remain after UV
irradiation.
Example 28
[0137] The manner was all the same as Example 14 with the exception
that the silicon wafer was immersed in pure water for 1 min and
immersed in 2-propanol (iPA) for 1 min after being immersed in
hydrofluoric acid aqueous solution at the above-mentioned "(2)
Cleaning of Silicon Wafer". As shown in the evaluation result of
Table 1, the contact angle after the surface treatment was
70.degree. and therefore the water repellency-providing effect was
exhibited. Additionally, the capillary force at the time where
water was retained was 1.1 MN/m.sup.2 and therefore the capillary
force was small. Additionally, the contact angle after UV
irradiation was smaller than 10.degree., so that removal of the
water repellency-provided surface condition was achieved.
Furthermore, the Ra value of the wafer after UV irradiation was
smaller than 0.5 nm, with which it was confirmed that the wafer was
not eroded at the time of cleaning and that the residue of the
water-repellent cleaning liquid did not remain after UV
irradiation.
Example 29
[0138] The manner was all the same as Example 20 with the exception
that the silicon wafer was immersed in pure water for 1 min and
immersed in 2-propanol (iPA) for 1 min after being immersed in
hydrofluoric acid aqueous solution at the above-mentioned "(2)
Cleaning of Silicon Wafer". As shown in the evaluation result of
Table 1, the contact angle after the surface treatment was
72.degree. and therefore the water repellency-providing effect was
exhibited. Additionally, the capillary force at the time where
water was retained was 1.0 MN/m.sup.2 and therefore the capillary
force was small. Additionally, the contact angle after UV
irradiation was smaller than 10.degree., so that removal of the
water repellency-provided surface condition was achieved.
Furthermore, the Ra value of the wafer after UV irradiation was
smaller than 0.5 nm, with which it was confirmed that the wafer was
not eroded at the time of cleaning and that the residue of the
water-repellent cleaning liquid did not remain after UV
irradiation.
Example 30
[0139] The manner was all the same as Example 21 with the exception
that the silicon wafer was immersed in pure water for 1 min and
immersed in 2-propanol (iPA) for 1 min after being immersed in
hydrofluoric acid aqueous solution at the above-mentioned "(2)
Cleaning of Silicon Wafer". As shown in the evaluation result of
Table 1, the contact angle after the surface treatment was
72.degree. and therefore the water repellency-providing effect was
exhibited. Additionally, the capillary force at the time where
water was retained was 1.0 MN/m.sup.2 and therefore the capillary
force was small. Additionally, the contact angle after UV
irradiation was smaller than 10.degree., so that removal of the
water repellency-provided surface condition was achieved.
Furthermore, the Ra value of the wafer after UV irradiation was
smaller than 0.5 nm, with which it was confirmed that the wafer was
not eroded at the time of cleaning and that the residue of the
water-repellent cleaning liquid did not remain after UV
irradiation.
Example 31
[0140] The manner was all the same as Example 1 with the exception
that the silicon wafer was immersed in pure water for 1 min,
immersed in 2-propanol (iPA) for 1 min and immersed in toluene for
1 min after being immersed in hydrofluoric acid aqueous solution at
the above-mentioned "(2) Cleaning of Silicon Wafer". As shown in
the evaluation result of Table 2, the contact angle after the
surface treatment was 74.degree. and therefore the water
repellency-providing effect was exhibited. Additionally, the
capillary force at the time where water was retained was 0.9
MN/m.sup.2 and therefore the capillary force was small.
Additionally, the contact angle after UV irradiation was smaller
than 10.degree., so that removal of the water repellency-provided
surface condition was achieved. Furthermore, the Ra value of the
wafer after UV irradiation was smaller than 0.5 nm, with which it
was confirmed that the wafer was not eroded at the time of cleaning
and that the residue of the water-repellent cleaning liquid did not
remain after UV irradiation.
Example 32
[0141] The manner was all the same as Example 9 with the exception
that the silicon wafer was immersed in pure water for 1 min,
immersed in 2-propanol (iPA) for 1 min and immersed in
hydrofluoroether (HFE-7100 produced by 3M Limited) for 1 min after
being immersed in hydrofluoric acid aqueous solution at the
above-mentioned "(2) Cleaning of Silicon Wafer". As shown in the
evaluation result of Table 2, the contact angle after the surface
treatment was 74.degree. and therefore the water
repellency-providing effect was exhibited. Additionally, the
capillary force at the time where water was retained was 0.9
MN/m.sup.2 and therefore the capillary force was small.
Additionally, the contact angle after UV irradiation was smaller
than 10.degree., so that removal of the water repellency-provided
surface condition was achieved. Furthermore, the Ra value of the
wafer after UV irradiation was smaller than 0.5 nm, with which it
was confirmed that the wafer was not eroded at the time of cleaning
and that the residue of the water-repellent cleaning liquid did not
remain after UV irradiation.
Example 33
[0142] The manner was all the same as Example 1 with the exception
that the silicon wafer was immersed in pure water for 1 min after
being immersed in hydrofluoric acid aqueous solution at the
above-mentioned "(2) Cleaning of Silicon Wafer". As shown in the
evaluation result of Table 2, the contact angle after the surface
treatment was 70.degree. and therefore the water
repellency-providing effect was exhibited. Additionally, the
capillary force at the time where water was retained was 1.1
MN/m.sup.2 and therefore the capillary force was small.
Additionally, the contact angle after UV irradiation was smaller
than 10.degree., so that removal of the water repellency-provided
surface condition was achieved. Furthermore, the Ra value of the
wafer after UV irradiation was smaller than 0.5 nm, with which it
was confirmed that the wafer was not eroded at the time of cleaning
and that the residue of the water-repellent cleaning liquid did not
remain after UV irradiation.
Example 34
[0143] The manner was all the same as Example 9 with the exception
that the silicon wafer was immersed in pure water for 1 min after
being immersed in hydrofluoric acid aqueous solution at the
above-mentioned "(2) Cleaning of Silicon Wafer". As shown in the
evaluation result of Table 2, the contact angle after the surface
treatment was 70.degree. and therefore the water
repellency-providing effect was exhibited. Additionally, the
capillary force at the time where water was retained was 1.1
MN/m.sup.2 and therefore the capillary force was small.
Additionally, the contact angle after UV irradiation was smaller
than 10.degree., so that removal of the water repellency-provided
surface condition was achieved. Furthermore, the Ra value of the
wafer after UV irradiation was smaller than 0.5 nm, with which it
was confirmed that the wafer was not eroded at the time of cleaning
and that the residue of the water-repellent cleaning liquid did not
remain after UV irradiation.
Example 35
[0144] The manner was all the same as Example 23 with the exception
that ethyldimethylchlorosilane [C.sub.2H.sub.5Si(CH.sub.3).sub.2Cl]
was used as the water-repellent compound. As shown in the
evaluation result of Table 2, the contact angle after the surface
treatment was 76.degree. and therefore the water
repellency-providing effect was exhibited. Additionally, the
capillary force at the time where water was retained was 0.8
MN/m.sup.2 and therefore the capillary force was small.
Additionally, the contact angle after UV irradiation was smaller
than 10.degree., so that removal of the water repellency-provided
surface condition was achieved. Furthermore, the Ra value of the
wafer after UV irradiation was smaller than 0.5 nm, with which it
was confirmed that the wafer was not eroded at the time of cleaning
and that the residue of the water-repellent cleaning liquid did not
remain after UV irradiation.
Example 36
[0145] The manner was all the same as Example 23 with the exception
that propyldimethylchlorosilane
[C.sub.3H.sub.7Si(CH.sub.3).sub.2Cl] was used as the
water-repellent compound. As shown in the evaluation result of
Table 2, the contact angle after the surface treatment was
80.degree. and therefore the water repellency-providing effect was
excellently exhibited. Additionally, the capillary force at the
time where water was retained was 0.6 MN/m.sup.2 and therefore the
capillary force was small. Additionally, the contact angle after UV
irradiation was smaller than 10.degree., so that removal of the
water repellency-provided surface condition was achieved.
Furthermore, the Ra value of the wafer after UV irradiation was
smaller than 0.5 nm, with which it was confirmed that the wafer was
not eroded at the time of cleaning and that the residue of the
water-repellent cleaning liquid did not remain after UV
irradiation.
Example 37
[0146] The manner was all the same as Example 3 with the exception
that the water-repellent cleaning liquid was obtained by setting
the water-repellent compound concentration to 5 mass % and by
adding 0.1 mass % trifluoroacetic acid relative to the total
quantity of 100 mass % of the water-repellent cleaning liquid. As
shown in the evaluation result of Table 2, the contact angle after
the surface treatment was 86.degree. and therefore the water
repellency-providing effect was exhibited. Additionally, the
capillary force at the time where water was retained was 0.2
MN/m.sup.2 and therefore the capillary force was small.
Additionally, the contact angle after UV irradiation was smaller
than 10.degree., so that removal of the water repellency-provided
surface condition was achieved. Furthermore, the Ra value of the
wafer after UV irradiation was smaller than 0.5 nm, with which it
was confirmed that the wafer was not eroded at the time of cleaning
and that the residue of the water-repellent cleaning liquid did not
remain after UV irradiation.
Example 38
[0147] The manner was all the same as Example 3 with the exception
that the water-repellent cleaning liquid was obtained by setting
the water-repellent compound concentration to 5 mass % and by
adding 0.1 mass % trifluoroacetic anhydride relative to the total
quantity of 100 mass % of the water-repellent cleaning liquid. As
shown in the evaluation result of Table 2, the contact angle after
the surface treatment was 86.degree. and therefore the water
repellency-providing effect was exhibited. Additionally, the
capillary force at the time where water was retained was 0.2
MN/m.sup.2 and therefore the capillary force was small.
Additionally, the contact angle after UV irradiation was smaller
than 10.degree., so that removal of the water repellency-provided
surface condition was achieved. Furthermore, the Ra value of the
wafer after UV irradiation was smaller than 0.5 nm, with which it
was confirmed that the wafer was not eroded at the time of cleaning
and that the residue of the water-repellent cleaning liquid did not
remain after UV irradiation.
Example 39
[0148] The manner was all the same as Example 37 with the exception
that the silicon wafer was immersed in pure water for 1 min and
immersed in 2-propanol (iPA) for 1 min after being immersed in
hydrofluoric acid aqueous solution at the above-mentioned "(2)
Cleaning of Silicon Wafer" and the HFE-7100 and PGMEA were used as
the organic solvent contained in the water-repellent cleaning
liquid at a mass ratio of 97:3. As shown in the evaluation result
of Table 2, the contact angle after the surface treatment was
86.degree. and therefore the water repellency-providing effect was
exhibited. Additionally, the capillary force at the time where
water was retained was 0.2 MN/m.sup.2 and therefore the capillary
force was small. Additionally, the contact angle after UV
irradiation was smaller than 10.degree., so that removal of the
water repellency-provided surface condition was achieved.
Furthermore, the Ra value of the wafer after UV irradiation was
smaller than 0.5 nm, with which it was confirmed that the wafer was
not eroded at the time of cleaning and that the residue of the
water-repellent cleaning liquid did not remain after UV
irradiation.
Example 40
[0149] The manner was all the same as Example 38 with the exception
that the silicon wafer was immersed in pure water for 1 min and
immersed in 2-propanol (iPA) for 1 min after being immersed in
hydrofluoric acid aqueous solution at the above-mentioned "(2)
Cleaning of Silicon Wafer" and the HFE-7100 and PGMEA were used as
the organic solvent contained in the water-repellent cleaning
liquid at a mass ratio of 97:3. As shown in the evaluation result
of Table 2, the contact angle after the surface treatment was
86.degree. and therefore the water repellency-providing effect was
exhibited. Additionally, the capillary force at the time where
water was retained was 0.2 MN/m.sup.2 and therefore the capillary
force was small. Additionally, the contact angle after UV
irradiation was smaller than 10.degree., so that removal of the
water repellency-provided surface condition was achieved.
Furthermore, the Ra value of the wafer after UV irradiation was
smaller than 0.5 nm, with which it was confirmed that the wafer was
not eroded at the time of cleaning and that the residue of the
water-repellent cleaning liquid did not remain after UV
irradiation.
Example 41
[0150] The manner was all the same as Example 39 with the exception
that PGMEA was used as the organic solvent contained in the
water-repellent cleaning liquid. As shown in the evaluation result
of Table 2, the contact angle after the surface treatment was
84.degree. and therefore the water repellency-providing effect was
exhibited. Additionally, the capillary force at the time where
water was retained was 0.3 MN/m.sup.2 and therefore the capillary
force was small. Additionally, the contact angle after UV
irradiation was smaller than 10.degree., so that removal of the
water repellency-provided surface condition was achieved.
Furthermore, the Ra value of the wafer after UV irradiation was
smaller than 0.5 nm, with which it was confirmed that the wafer was
not eroded at the time of cleaning and that the residue of the
water-repellent cleaning liquid did not remain after UV
irradiation.
Example 42
[0151] The manner was all the same as Example 40 with the exception
that PGMEA was used as the organic solvent contained in the
water-repellent cleaning liquid. As shown in the evaluation result
of Table 2, the contact angle after the surface treatment was
84.degree. and therefore the water repellency-providing effect was
exhibited. Additionally, the capillary force at the time where
water was retained was 0.3 MN/m.sup.2 and therefore the capillary
force was small. Additionally, the contact angle after UV
irradiation was smaller than 10.degree., so that removal of the
water repellency-provided surface condition was achieved.
Furthermore, the Ra value of the wafer after UV irradiation was
smaller than 0.5 nm, with which it was confirmed that the wafer was
not eroded at the time of cleaning and that the residue of the
water-repellent cleaning liquid did not remain after UV
irradiation.
Example 43
[0152] The manner was all the same as Example 41 with the exception
that, at the above-mentioned "(3) Surface Treatment of Silicon
Wafer Surface by Water-Repellent Cleaning Liquid", the silicon
wafer was immersed in 2-propanol for 1 min after being immersed in
the water-repellent cleaning liquid and that the silicon wafer was
finally taken out of 2-propanol, followed by spraying air thereon
to remove 2-propanol from the surface thereby obtaining a wafer
provided with a water repellency-provided surface condition. As
shown in the evaluation result of Table 2, the contact angle after
the surface treatment was 84.degree. and therefore the water
repellency-providing effect was exhibited. Additionally, the
capillary force at the time where water was retained was 0.3
MN/m.sup.2 and therefore the capillary force was small.
Additionally, the contact angle after UV irradiation was smaller
than 10.degree., so that removal of the water repellency-provided
surface condition was achieved. Furthermore, the Ra value of the
wafer after UV irradiation was smaller than 0.5 nm, with which it
was confirmed that the wafer was not eroded at the time of cleaning
and that the residue of the water-repellent cleaning liquid did not
remain after UV irradiation.
Example 44
[0153] The manner was all the same as Example 42 with the exception
that, at the above-mentioned "(3) Surface Treatment of Silicon
Wafer Surface by Water-Repellent Cleaning Liquid", the silicon
wafer was immersed in 2-propanol for 1 min after being immersed in
the water-repellent cleaning liquid and that the silicon wafer was
finally taken out of 2-propanol, followed by spraying air thereon
to remove 2-propanol from the surface thereby obtaining a wafer
provided with a water repellency-provided surface condition. As
shown in the evaluation result of Table 2, the contact angle after
the surface treatment was 84.degree. and therefore the water
repellency-providing effect was exhibited. Additionally, the
capillary force at the time where water was retained was 0.3
MN/m.sup.2 and therefore the capillary force was small.
Additionally, the contact angle after UV irradiation was smaller
than 10.degree., so that removal of the water repellency-provided
surface condition was achieved. Furthermore, the Ra value of the
wafer after UV irradiation was smaller than 0.5 nm, with which it
was confirmed that the wafer was not eroded at the time of cleaning
and that the residue of the water-repellent cleaning liquid did not
remain after UV irradiation.
Comparative Example 1
[0154] The manner was the same as Example 1 with the exception that
the water-repellent cleaning liquid was not provided to the silicon
wafer. In other words, in this Comparative Example, a wafer which
is in a surface condition not provided with water repellency was
evaluated. As shown in the evaluation result of Table 2, the
contact angle of the wafer was 3.degree., i.e. small, while the
capillary force at the time where water was retained was 3.2
MN/m.sup.2, i.e. large.
Comparative Example 2
[0155] The manner was the same as Example 1 with the exception that
3.0 g of trimethylchlorosilane [(CH.sub.3).sub.3SiCl] was mixed
with 94.6 g of 2-propanol (iPA), followed by adding 2.4 g of 0.1N
nitric acid aqueous solution (pH 1.0) and stirring at room
temperature for about 24 hours thereby obtaining a water-repellent
cleaning liquid. In other words, in this Comparative Example, a
water-repellent cleaning liquid containing a water-repellent
compound hydrolyzed at its reactive moiety was used. As shown in
the evaluation result of Table 2, the contact angle after the
surface treatment was 20.degree., i.e. small, while the capillary
force at the time where water was retained was 2.7 MN/m.sup.2, i.e.
large.
[0156] The following Examples 1 to 31 exemplifies a second cleaning
agent while the following Comparative Examples 1 and 2 are opposed
to the second cleaning agent. Results of these are shown in Table
3.
Example 1
(1) Preparation of Water-Repellent Cleaning Liquid
[0157] A mixture of 3 g of trimethylchlorosilane
[(CH.sub.3).sub.3SiCl] serving as a water-repellent compound, 10 g
of N,N-dimethylformamide serving as a nitrogen containing solvent
and 87 g of toluene serving as an organic solvent other than the
nitrogen containing solvent was stirred for 5 min thereby obtaining
a water-repellent cleaning liquid having; a concentration of the
water-repellent compound relative to the total quantity of the
water-repellent cleaning liquid (hereinafter referred to as "a
water-repellent compound concentration") of 3 mass %; and a
concentration of the nitrogen containing solvent relative to the
total quantity of the water-repellent cleaning liquid (hereinafter
referred to as "a nitrogen-containing compound concentration") of
10 mass %.
(2) Cleaning of Silicon Wafer
[0158] An even silicon wafer with a thermal oxide film (A Si wafer
having on its surface a thermal oxide film layer of 1 micrometer
thickness) was immersed in 1 mass % hydrofluoric acid aqueous
solution for 2 min, followed by being immersed in pure water for 1
min and then in acetone for 1 min.
(3) Surface Treatment of Silicon Wafer Surface by Water-Repellent
Cleaning Liquid
[0159] The silicon wafer was immersed in the water-repellent
cleaning liquid prepared at the above-mentioned "(1) Preparation of
Water-Repellent Cleaning Liquid" at 20.degree. C. for 10 min.
Thereafter, the silicon wafer was immersed in 2-propanol for 1 min
and then immersed in pure water for 1 min. Finally, the silicon
wafer was taken out of the pure water, followed by spraying air
thereon, thereby removing the pure water from the surface.
[0160] As a result of evaluating the obtained wafer in a manner as
discussed in the [Evaluation Method For Silicon Wafer To Which
Water-Repellent Cleaning Liquid Is Provided], one having had an
initial contact angle of smaller than 10.degree. before a surface
treatment changed to have a contact angle of 80.degree. after the
surface treatment, as shown in Table 3, thereby exhibiting an
excellent water repellency-providing effect. Additionally, as a
result of calculating the capillary force at the time where water
was retained, the capillary force was 0.6 MN/m.sup.2 and therefore
the capillary force was small. Additionally, the contact angle
after UV irradiation was smaller than 10.degree., so that removal
of the water repellency-provided surface condition was achieved.
Furthermore, the Ra value of the wafer after UV irradiation was
smaller than 0.5 nm, with which it was confirmed that the wafer was
not eroded at the time of cleaning and that the residue of the
water-repellent cleaning liquid did not remain after UV
irradiation.
TABLE-US-00003 TABLE 3 Water-repellent cleaning liquid Treatment of
Organic solvent water-repellent Nitrogen- cleaning liquid Water-
containing before surface repellent solvent treatment compound
Nitrogen- concen- Other Solvent used for Immersion Water-repellent
concentration containing tration organic cleaning after Temperature
Time compound [mass %] solvent [mass %] solvent rinsing with water
[.degree. C.] [min] Example 1 (CH.sub.3).sub.3SiCl 3 DMF 10 Toluene
Acetone 20 10 Example 2 (CH.sub.3).sub.3SiCl 1 DMF 10 Toluene
Acetone 20 10 Example 3 (CH.sub.3).sub.3SiCl 3 DMF 2 Toluene
Acetone 20 10 Example 4 (CH.sub.3).sub.3SiCl 3 NMP 10 Toluene
Acetone 20 10 Example 5
CF.sub.3CH.sub.2CH.sub.2Si(CH.sub.3).sub.2Cl 3 DMF 10 Toluene
Acetone 20 10 Example 6
CF.sub.3CH.sub.2CH.sub.2Si(CH.sub.3)Cl.sub.2 3 DMF 10 Toluene
Acetone 20 10 Example 7 (CH.sub.3).sub.3SiCl 3 DMF 10 HFE-7100
Acetone 20 10 Example 8 (CH.sub.3).sub.3SiCl 3 DMF 10 DCTFP Acetone
20 10 Example 9 (CH.sub.3).sub.3SiCl 3 DMF 10 CTFP Acetone 20 10
Example 10 (CH.sub.3).sub.3SiCl 3 DMF 10 HFE-7100 Acetone 20 10
Example 11 (CH.sub.3).sub.3SiCl 3 DMF 10 DCTFP Acetone 20 10
Example 12 (CH.sub.3).sub.3SiCl 3 DMF 10 HFE-7100 Acetone 20 10
Example 13 (CH.sub.3).sub.3SiCl 3 DMF 10 DCTFP Acetone 20 10
Example 14 (CH.sub.3).sub.3SiCl 3 DMF 10 DCTFP Acetone 20 10
Example 15 (CH.sub.3).sub.3SiCl 3 DMF 10 DCTFP Acetone 20 10
Example 16 (CH.sub.3).sub.3SiCl 3 DMF 10 DCTFP Acetone 20 10
Example 17 (CH.sub.3).sub.3SiCl 3 DMF 10 HFE-7100 Acetone 20 10
Example 18 (CH.sub.3).sub.3SiCl 3 DMF 10 DCTFP Acetone 20 10
Example 19 (CH.sub.3).sub.3SiCl 3 DMF 10 Toluene iPA 20 10 Example
20 (CH.sub.3).sub.3SiCl 3 DMF 10 HFE-7100 iPA 20 10 Example 21
(CH.sub.3).sub.3SiCl 3 DMF 10 DCTFP iPA 20 10 Example 22
(CH.sub.3).sub.3SiCl 3 DMF 10 HFE-7100 iPA 20 10 Example 23
(CH.sub.3).sub.3SiCl 3 DMF 10 DCTFP iPA 20 10 Example 24
(CH.sub.3).sub.3SiCl 3 DMF 10 HFE-7100 iPA 20 10 Example 25
(CH.sub.3).sub.3SiCl 3 DMF 10 DCTFP iPA 20 10 Example 26
(CH.sub.3).sub.3SiCl 3 DMF 10 Toluene iPA, Toluene 20 10 Example 27
(CH.sub.3).sub.3SiCl 3 DMF 10 HFE-7100 iPA, HFE-7100 20 10 Example
28 (CH.sub.3).sub.3SiCl 3 DMF 10 Toluene None 20 10 Example 29
(CH.sub.3).sub.3SiCl 3 DMF 10 HFE-7100 None 20 10 Example 30
C.sub.2H.sub.5Si(CH.sub.3).sub.2Cl 3 DMF 10 HFE-7100 iPA 20 10
Example 31 C.sub.3H.sub.7Si(CH.sub.3).sub.2Cl 3 DMF 10 HFE-7100 iPA
20 10 Comparative Not treated -- -- -- -- Acetone -- -- Example 1
Comparative Hydrolysate of 3 DMF 10 iPA Acetone 20 10 Example 2
(CH.sub.3).sub.3SiCl Evaluation results Removability of water-
Treatment of water-repellent cleaning Contact Capillary repellent
liquid after surface treatment Initial angle after force surface
Cleaning Cleaning contact surface [MN/m.sup.2] condition Surface
with with angle treatment <calculated (contact roughness Drying
solvent water Drying [.degree.] [.degree.] value> angle
[.degree.]) (Ra [nm]) Example 1 Not done Done Done Done <10 A
(80) A (0.6) A (<10) A (<0.5) Example 2 Not done Done Done
Done <10 A (72) A (1.0) A (<10) A (<0.5) Example 3 Not
done Done Done Done <10 A (78) A (0.7) A (<10) A (<0.5)
Example 4 Not done Done Done Done <10 A (74) A (0.9) A (<10)
A (<0.5) Example 5 Not done Done Done Done <10 A (80) A (0.6)
A (<10) A (<0.5) Example 6 Not done Done Done Done <10 A
(74) A (0.9) A (<10) A (<0.5) Example 7 Not done Done Done
Done <10 A (80) A (0.6) A (<10) A (<0.5) Example 8 Not
done Done Done Done <10 A (78) A (0.7) A (<10) A (<0.5)
Example 9 Not done Done Done Done <10 A (78) A (0.7) A (<10)
A (<0.5) Example 10 Not done Done Not done Done <10 A (80) A
(0.6) A (<10) A (<0.5) Example 11 Not done Done Not done Done
<10 A (78) A (0.7) A (<10) A (<0.5) Example 12 Not done
Not done Done Done <10 A (80) A (0.6) A (<10) A (<0.5)
Example 13 Not done Not done Done Done <10 A (78) A (0.7) A
(<10) A (<0.5) Example 14 Done Done Done Done <10 A (80) A
(0.6) A (<10) A (<0.5) Example 15 Done Done Not done Done
<10 A (80) A (0.6) A (<10) A (<0.5) Example 16 Done Not
done Done Done <10 A (80) A (0.6) A (<10) A (<0.5) Example
17 Done Not done Not done Not done <10 A (82) A (0.5) A (<10)
A (<0.5) Example 18 Done Not done Not done Not done <10 A
(80) A (0.6) A (<10) A (<0.5) Example 19 Not done Done Done
Done <10 A (78) A (0.7) A (<10) A (<0.5) Example 20 Not
done Done Done Done <10 A (78) A (0.7) A (<10) A (<0.5)
Example 21 Not done Done Done Done <10 A (78) A (0.7) A (<10)
A (<0.5) Example 22 Not done Done Not done Done <10 A (78) A
(0.7) A (<10) A (<0.5) Example 23 Not done Done Not done Done
<10 A (76) A (0.8) A (<10) A (<0.5) Example 24 Done Not
done Not done Not done <10 A (80) A (0.6) A (<10) A (<0.5)
Example 25 Done Not done Not done Not done <10 A (78) A (0.7) A
(<10) A (<0.5) Example 26 Not done Done Done Done <10 A
(78) A (0.7) A (<10) A (<0.5) Example 27 Not done Done Done
Done <10 A (78) A (0.7) A (<10) A (<0.5) Example 28 Not
done Done Done Done <10 A (78) A (0.7) A (<10) A (<0.5)
Example 29 Not done Done Done Done <10 A (78) A (0.7) A (<10)
A (<0.5) Example 30 Not done Done Done Done <10 A (80) A
(0.6) A (<10) A (<0.5) Example 31 Not done Done Done Done
<10 A (84) A (0.3) A (<10) A (<0.5) Comparative Not done
Done Done Done <10 B (3) B (3.2) -- A (<0.5) Example 1
Comparative Not done Done Done Done <10 B (15) B (3.1) -- --
Example 2
Example 2
[0161] The manner was all the same as Example 1 with the exception
that the water-repellent compound concentration was set to 1 mass
%. As shown in the evaluation result of Table 3, the contact angle
after the surface treatment was 72.degree. and therefore the water
repellency-providing effect was exhibited. Additionally, the
capillary force at the time where water was retained was 1.0
MN/m.sup.2 and therefore the capillary force was small.
Additionally, the contact angle after UV irradiation was smaller
than 10.degree., so that removal of the water repellency-provided
surface condition was achieved. Furthermore, the Ra value of the
wafer after UV irradiation was smaller than 0.5 nm, with which it
was confirmed that the wafer was not eroded at the time of cleaning
and that the residue of the water-repellent cleaning liquid did not
remain after UV irradiation.
Example 3
[0162] The manner was all the same as Example 1 with the exception
that the nitrogen-containing compound concentration was set to 2
mass %. As shown in the evaluation result of Table 3, the contact
angle after the surface treatment was 78.degree. and therefore the
water repellency-providing effect was exhibited. Additionally, the
capillary force at the time where water was retained was 0.7
MN/m.sup.2 and therefore the capillary force was small.
Additionally, the contact angle after UV irradiation was smaller
than 10.degree., so that removal of the water repellency-provided
surface condition was achieved. Furthermore, the Ra value of the
wafer after UV irradiation was smaller than 0.5 nm, with which it
was confirmed that the wafer was not eroded at the time of cleaning
and that the residue of the water-repellent cleaning liquid did not
remain after UV irradiation.
Example 4
[0163] The manner was all the same as Example 1 with the exception
that N-methyl-2-pyrrolidone (NMP) was used as the nitrogen
containing solvent. As shown in the evaluation result of Table 3,
the contact angle after the surface treatment was 74.degree. and
therefore the water repellency-providing effect was exhibited.
Additionally, the capillary force at the time where water was
retained was 0.9 MN/m.sup.2 and therefore the capillary force was
small. Additionally, the contact angle after UV irradiation was
smaller than 10.degree., so that removal of the water
repellency-provided surface condition was achieved. Furthermore,
the Ra value of the wafer after UV irradiation was smaller than 0.5
nm, with which it was confirmed that the wafer was not eroded at
the time of cleaning and that the residue of the water-repellent
cleaning liquid did not remain after UV irradiation.
Example 5
[0164] The manner was all the same as Example 1 with the exception
that (trifluoropropyl)dimethylchlorosilane
[CF.sub.3CH.sub.2CH.sub.2Si(CH.sub.3).sub.2Cl] was used as the
water-repellent compound. As shown in the evaluation result of
Table 3, the contact angle after the surface treatment was
80.degree. and therefore the water repellency-providing effect was
excellently exhibited. Additionally, the capillary force at the
time where water was retained was 0.6 MN/m.sup.2 and therefore the
capillary force was small. Additionally, the contact angle after UV
irradiation was smaller than 10.degree., so that removal of the
water repellency-provided surface condition was achieved.
Furthermore, the Ra value of the wafer after UV irradiation was
smaller than 0.5 nm, with which it was confirmed that the wafer was
not eroded at the time of cleaning and that the residue of the
water-repellent cleaning liquid did not remain after UV
irradiation.
Example 6
[0165] The manner was all the same as Example 1 with the exception
that (trifluoropropyl)methyldichlorosilane
[CF.sub.3CH.sub.2CH.sub.2Si(CH.sub.3)Cl.sub.2] was used as the
water-repellent compound. As shown in the evaluation result of
Table 3, the contact angle after the surface treatment was
74.degree. and therefore the water repellency-providing effect was
exhibited. Additionally, the capillary force at the time where
water was retained was 0.9 MN/m.sup.2 and therefore the capillary
force was small. Additionally, the contact angle after UV
irradiation was smaller than 10.degree., so that removal of the
water repellency-provided surface condition was achieved.
Furthermore, the Ra value of the wafer after UV irradiation was
smaller than 0.5 nm, with which it was confirmed that the wafer was
not eroded at the time of cleaning and that the residue of the
water-repellent cleaning liquid did not remain after UV
irradiation.
Example 7
[0166] The manner was all the same as Example 1 with the exception
that hydrofluoroether (HFE-7100 produced by 3M Limited) was used as
the organic solvent which is other than the nitrogen-containing and
contained in the water-repellent cleaning liquid. As shown in the
evaluation result of Table 3, the contact angle after the surface
treatment was 80.degree. and therefore the water
repellency-providing effect was excellently exhibited.
Additionally, the capillary force at the time where water was
retained was 0.6 MN/m.sup.2 and therefore the capillary force was
small. Additionally, the contact angle after UV irradiation was
smaller than 10.degree., so that removal of the water
repellency-provided surface condition was achieved. Furthermore,
the Ra value of the wafer after UV irradiation was smaller than 0.5
nm, with which it was confirmed that the wafer was not eroded at
the time of cleaning and that the residue of the water-repellent
cleaning liquid did not remain after UV irradiation.
Example 8
[0167] The manner was all the same as Example 1 with the exception
that cis-1,2-dichloro-3,3,3-trifluoropropene (DCTFP) was used as
the organic solvent which is other than the nitrogen-containing and
contained in the water-repellent cleaning liquid. As shown in the
evaluation result of Table 3, the contact angle after the surface
treatment was 78.degree. and therefore the water
repellency-providing effect was exhibited. Additionally, the
capillary force at the time where water was retained was 0.7
MN/m.sup.2 and therefore the capillary force was small.
Additionally, the contact angle after UV irradiation was smaller
than 10.degree., so that removal of the water repellency-provided
surface condition was achieved. Furthermore, the Ra value of the
wafer after UV irradiation was smaller than 0.5 nm, with which it
was confirmed that the wafer was not eroded at the time of cleaning
and that the residue of the water-repellent cleaning liquid did not
remain after UV irradiation.
Example 9
[0168] The manner was all the same as Example 1 with the exception
that 1-chloro-3,3,3-trifluoropropene (CTFP) was used as the organic
solvent which is other than the nitrogen-containing and contained
in the water-repellent cleaning liquid. As shown in the evaluation
result of Table 3, the contact angle after the surface treatment
was 78.degree. and therefore the water repellency-providing effect
was exhibited. Additionally, the capillary force at the time where
water was retained was 0.7 MN/m.sup.2 and therefore the capillary
force was small. Additionally, the contact angle after UV
irradiation was smaller than 10.degree., so that removal of the
water repellency-provided surface condition was achieved.
Furthermore, the Ra value of the wafer after UV irradiation was
smaller than 0.5 nm, with which it was confirmed that the wafer was
not eroded at the time of cleaning and that the residue of the
water-repellent cleaning liquid did not remain after UV
irradiation.
Example 10
[0169] The manner was all the same as Example 7 with the exception
that, at the above-mentioned "(3) Surface Treatment of Silicon
Wafer Surface by Water-Repellent Cleaning Liquid", the silicon
wafer was immersed in 2-propanol for 1 min after being immersed in
the water-repellent cleaning liquid and that the silicon wafer was
finally taken out of 2-propanol, followed by spraying air thereon
to remove 2-propanol from the surface thereby obtaining a wafer
provided with a water repellency-provided surface condition. As
shown in the evaluation result of Table 3, the contact angle after
the surface treatment was 80.degree. and therefore the water
repellency-providing effect was excellently exhibited.
Additionally, the capillary force at the time where water was
retained was 0.6 MN/m.sup.2 and therefore the capillary force was
small. Additionally, the contact angle after UV irradiation was
smaller than 10.degree., so that removal of the water
repellency-provided surface condition was achieved. Furthermore,
the Ra value of the wafer after UV irradiation was smaller than 0.5
nm, with which it was confirmed that the wafer was not eroded at
the time of cleaning and that the residue of the water-repellent
cleaning liquid did not remain after UV irradiation.
Example 11
[0170] The manner was all the same as Example 10 with the exception
that DCTFP was used as the organic solvent which is other than the
nitrogen-containing and contained in the water-repellent cleaning
liquid. As shown in the evaluation result of Table 3, the contact
angle after the surface treatment was 78.degree. and therefore the
water repellency-providing effect was exhibited. Additionally, the
capillary force at the time where water was retained was 0.7
MN/m.sup.2 and therefore the capillary force was small.
Additionally, the contact angle after UV irradiation was smaller
than 10.degree., so that removal of the water repellency-provided
surface condition was achieved. Furthermore, the Ra value of the
wafer after UV irradiation was smaller than 0.5 nm, with which it
was confirmed that the wafer was not eroded at the time of cleaning
and that the residue of the water-repellent cleaning liquid did not
remain after UV irradiation.
Example 12
[0171] The manner was all the same as Example 7 with the exception
that, at the above-mentioned "(3) Surface Treatment of Silicon
Wafer Surface by Water-Repellent Cleaning Liquid", the silicon
wafer was immersed in pure water for 1 min after being immersed in
the water-repellent cleaning liquid and that the silicon wafer was
finally taken out of the pure water, followed by spraying air
thereon thereby obtaining a wafer provided with a water
repellency-provided surface condition. As shown in the evaluation
result of Table 3, the contact angle after the surface treatment
was 80.degree. and therefore the water repellency-providing effect
was excellently exhibited. Additionally, the capillary force at the
time where water was retained was 0.6 MN/m.sup.2 and therefore the
capillary force was small. Additionally, the contact angle after UV
irradiation was smaller than 10.degree., so that removal of the
water repellency-provided surface condition was achieved.
Furthermore, the Ra value of the wafer after UV irradiation was
smaller than 0.5 nm, with which it was confirmed that the wafer was
not eroded at the time of cleaning and that the residue of the
water-repellent cleaning liquid did not remain after UV
irradiation.
Example 13
[0172] The manner was all the same as Example 12 with the exception
that DCTFP was used as the organic solvent which is other than the
nitrogen-containing and contained in the water-repellent cleaning
liquid. As shown in the evaluation result of Table 3, the contact
angle after the surface treatment was 78.degree. and therefore the
water repellency-providing effect was exhibited. Additionally, the
capillary force at the time where water was retained was 0.7
MN/m.sup.2 and therefore the capillary force was small.
Additionally, the contact angle after UV irradiation was smaller
than 10.degree., so that removal of the water repellency-provided
surface condition was achieved. Furthermore, the Ra value of the
wafer after UV irradiation was smaller than 0.5 nm, with which it
was confirmed that the wafer was not eroded at the time of cleaning
and that the residue of the water-repellent cleaning liquid did not
remain after UV irradiation.
Example 14
[0173] The manner was all the same as Example 8 with the exception
that, at the above-mentioned "(3) Surface Treatment of Silicon
Wafer Surface by Water-Repellent Cleaning Liquid", the silicon
wafer was immersed in the water-repellent cleaning liquid, followed
by spraying air thereon to remove the water-repellent cleaning
liquid from its surface, and subsequently the silicon wafer was
immersed in 2-propanol for 1 min and immersed in pure water for 1
min and finally taken out of the pure water, followed by spraying
air thereon to remove the pure water from the surface thereby
obtaining a wafer provided with a water repellency-provided surface
condition. As shown in the evaluation result of Table 3, the
contact angle after the surface treatment was 80.degree. and
therefore the water repellency-providing effect was excellently
exhibited. Additionally, the capillary force at the time where
water was retained was 0.6 MN/m.sup.2 and therefore the capillary
force was small. Additionally, the contact angle after UV
irradiation was smaller than 10.degree., so that removal of the
water repellency-provided surface condition was achieved.
Furthermore, the Ra value of the wafer after UV irradiation was
smaller than 0.5 nm, with which it was confirmed that the wafer was
not eroded at the time of cleaning and that the residue of the
water-repellent cleaning liquid did not remain after UV
irradiation.
Example 15
[0174] The manner was all the same as Example 8 with the exception
that, at the above-mentioned "(3) Surface Treatment of Silicon
Wafer Surface by Water-Repellent Cleaning Liquid", the silicon
wafer was immersed in the water-repellent cleaning liquid, followed
by spraying air thereon to remove the water-repellent cleaning
liquid from its surface, and subsequently the silicon wafer was
immersed in 2-propanol for 1 min and finally taken out of
2-propanol, followed by spraying air thereon to remove 2-propanol
from the surface thereby obtaining a wafer provided with a water
repellency-provided surface condition. As shown in the evaluation
result of Table 3, the contact angle after the surface treatment
was 80.degree. and therefore the water repellency-providing effect
was excellently exhibited. Additionally, the capillary force at the
time where water was retained was 0.6 MN/m.sup.2 and therefore the
capillary force was small. Additionally, the contact angle after UV
irradiation was smaller than 10.degree., so that removal of the
water repellency-provided surface condition was achieved.
Furthermore, the Ra value of the wafer after UV irradiation was
smaller than 0.5 nm, with which it was confirmed that the wafer was
not eroded at the time of cleaning and that the residue of the
water-repellent cleaning liquid did not remain after UV
irradiation.
Example 16
[0175] The manner was all the same as Example 8 with the exception
that, at the above-mentioned "(3) Surface Treatment of Silicon
Wafer Surface by Water-Repellent Cleaning Liquid", the silicon
wafer was immersed in the water-repellent cleaning liquid, followed
by spraying air thereon to remove the water-repellent cleaning
liquid from its surface, and subsequently the silicon wafer was
immersed in pure water for 1 min and finally taken out of the pure
water, followed by spraying air thereon to remove the pure water
from the surface thereby obtaining a wafer provided with a water
repellency-provided surface condition. As shown in the evaluation
result of Table 3, the contact angle after the surface treatment
was 80.degree. and therefore the water repellency-providing effect
was excellently exhibited. Additionally, the capillary force at the
time where water was retained was 0.6 MN/m.sup.2 and therefore the
capillary force was small. Additionally, the contact angle after UV
irradiation was smaller than 10.degree., so that removal of the
water repellency-provided surface condition was achieved.
Furthermore, the Ra value of the wafer after UV irradiation was
smaller than 0.5 nm, with which it was confirmed that the wafer was
not eroded at the time of cleaning and that the residue of the
water-repellent cleaning liquid did not remain after UV
irradiation.
Example 17
[0176] The manner was all the same as Example 7 with the exception
that, at the above-mentioned "(3) Surface Treatment of Silicon
Wafer Surface by Water-Repellent Cleaning Liquid": air was sprayed
on the silicon wafer after taking the silicon wafer out of the
water-repellent cleaning liquid thereby obtaining a wafer provided
with a water repellency-provided surface condition. As shown in the
evaluation result of Table 3, the contact angle after the surface
treatment was 82.degree. and therefore the water
repellency-providing effect was excellently exhibited.
Additionally, the capillary force at the time where water was
retained was 0.5 MN/m.sup.2 and therefore the capillary force was
small. Additionally, the contact angle after UV irradiation was
smaller than 10.degree., so that removal of the water
repellency-provided surface condition was achieved. Furthermore,
the Ra value of the wafer after UV irradiation was smaller than 0.5
nm, with which it was confirmed that the wafer was not eroded at
the time of cleaning and that the residue of the water-repellent
cleaning liquid did not remain after UV irradiation.
Example 18
[0177] The manner was all the same as Example 17 with the exception
that DCTFP was used as the organic solvent which is other than the
nitrogen-containing and contained in the water-repellent cleaning
liquid. As shown in the evaluation result of Table 3, the contact
angle after the surface treatment was 80.degree. and therefore the
water repellency-providing effect was excellently exhibited.
Additionally, the capillary force at the time where water was
retained was 0.6 MN/m.sup.2 and therefore the capillary force was
small. Additionally, the contact angle after UV irradiation was
smaller than 10.degree., so that removal of the water
repellency-provided surface condition was achieved. Furthermore,
the Ra value of the wafer after UV irradiation was smaller than 0.5
nm, with which it was confirmed that the wafer was not eroded at
the time of cleaning and that the residue of the water-repellent
cleaning liquid did not remain after UV irradiation.
Example 19
[0178] The manner was all the same as Example 1 with the exception
that the silicon wafer was immersed in pure water for 1 min and
immersed in 2-propanol (iPA) for 1 min after being immersed in
hydrofluoric acid aqueous solution at the above-mentioned "(2)
Cleaning of Silicon Wafer". As shown in the evaluation result of
Table 3, the contact angle after the surface treatment was
78.degree. and therefore the water repellency-providing effect was
exhibited. Additionally, the capillary force at the time where
water was retained was 0.7 MN/m.sup.2 and therefore the capillary
force was small. Additionally, the contact angle after UV
irradiation was smaller than 10.degree., so that removal of the
water repellency-provided surface condition was achieved.
Furthermore, the Ra value of the wafer after UV irradiation was
smaller than 0.5 nm, with which it was confirmed that the wafer was
not eroded at the time of cleaning and that the residue of the
water-repellent cleaning liquid did not remain after UV
irradiation.
Example 20
[0179] The manner was all the same as Example 19 with the exception
that HFE-7100 was used as the organic solvent which is other than
the nitrogen-containing and contained in the water-repellent
cleaning liquid. As shown in the evaluation result of Table 3, the
contact angle after the surface treatment was 78.degree. and
therefore the water repellency-providing effect was excellently
exhibited. Additionally, the capillary force at the time where
water was retained was 0.7 MN/m.sup.2 and therefore the capillary
force was small. Additionally, the contact angle after UV
irradiation was smaller than 10.degree., so that removal of the
water repellency-provided surface condition was achieved.
Furthermore, the Ra value of the wafer after UV irradiation was
smaller than 0.5 nm, with which it was confirmed that the wafer was
not eroded at the time of cleaning and that the residue of the
water-repellent cleaning liquid did not remain after UV
irradiation.
Example 21
[0180] The manner was all the same as Example 19 with the exception
that DCTFP was used as the organic solvent which is other than the
nitrogen-containing and contained in the water-repellent cleaning
liquid. As shown in the evaluation result of Table 3, the contact
angle after the surface treatment was 78.degree. and therefore the
water repellency-providing effect was excellently exhibited.
Additionally, the capillary force at the time where water was
retained was 0.7 MN/m.sup.2 and therefore the capillary force was
small. Additionally, the contact angle after UV irradiation was
smaller than 10.degree., so that removal of the water
repellency-provided surface condition was achieved. Furthermore,
the Ra value of the wafer after UV irradiation was smaller than 0.5
nm, with which it was confirmed that the wafer was not eroded at
the time of cleaning and that the residue of the water-repellent
cleaning liquid did not remain after UV irradiation.
Example 22
[0181] The manner was all the same as Example 10 with the exception
that the silicon wafer was immersed in pure water for 1 min and
immersed in 2-propanol (iPA) for 1 min after being immersed in
hydrofluoric acid aqueous solution at the above-mentioned "(2)
Cleaning of Silicon Wafer". As shown in the evaluation result of
Table 3, the contact angle after the surface treatment was
78.degree. and therefore the water repellency-providing effect was
exhibited. Additionally, the capillary force at the time where
water was retained was 0.7 MN/m.sup.2 and therefore the capillary
force was small. Additionally, the contact angle after UV
irradiation was smaller than 10.degree., so that removal of the
water repellency-provided surface condition was achieved.
Furthermore, the Ra value of the wafer after UV irradiation was
smaller than 0.5 nm, with which it was confirmed that the wafer was
not eroded at the time of cleaning and that the residue of the
water-repellent cleaning liquid did not remain after UV
irradiation.
Example 23
[0182] The manner was all the same as Example 22 with the exception
that DCTFP was used as the organic solvent which is other than the
nitrogen-containing and contained in the water-repellent cleaning
liquid. As shown in the evaluation result of Table 3, the contact
angle after the surface treatment was 76.degree. and therefore the
water repellency-providing effect was excellently exhibited.
Additionally, the capillary force at the time where water was
retained was 0.8 MN/m.sup.2 and therefore the capillary force was
small. Additionally, the contact angle after UV irradiation was
smaller than 10.degree., so that removal of the water
repellency-provided surface condition was achieved. Furthermore,
the Ra value of the wafer after UV irradiation was smaller than 0.5
nm, with which it was confirmed that the wafer was not eroded at
the time of cleaning and that the residue of the water-repellent
cleaning liquid did not remain after UV irradiation.
Example 24
[0183] The manner was all the same as Example 17 with the exception
that the silicon wafer was immersed in pure water for 1 min and
immersed in 2-propanol (iPA) for 1 min after being immersed in
hydrofluoric acid aqueous solution at the above-mentioned "(2)
Cleaning of Silicon Wafer". As shown in the evaluation result of
Table 3, the contact angle after the surface treatment was
80.degree. and therefore the water repellency-providing effect was
excellently exhibited. Additionally, the capillary force at the
time where water was retained was 0.6 MN/m.sup.2 and therefore the
capillary force was small. Additionally, the contact angle after UV
irradiation was smaller than 10.degree., so that removal of the
water repellency-provided surface condition was achieved.
Furthermore, the Ra value of the wafer after UV irradiation was
smaller than 0.5 nm, with which it was confirmed that the wafer was
not eroded at the time of cleaning and that the residue of the
water-repellent cleaning liquid did not remain after UV
irradiation.
Example 25
[0184] The manner was all the same as Example 24 with the exception
that DCTFP was used as the organic solvent which is other than the
nitrogen-containing and contained in the water-repellent cleaning
liquid. As shown in the evaluation result of Table 3, the contact
angle after the surface treatment was 78.degree. and therefore the
water repellency-providing effect was excellently exhibited.
Additionally, the capillary force at the time where water was
retained was 0.7 MN/m.sup.2 and therefore the capillary force was
small. Additionally, the contact angle after UV irradiation was
smaller than 10.degree., so that removal of the water
repellency-provided surface condition was achieved. Furthermore,
the Ra value of the wafer after UV irradiation was smaller than 0.5
nm, with which it was confirmed that the wafer was not eroded at
the time of cleaning and that the residue of the water-repellent
cleaning liquid did not remain after UV irradiation.
Example 26
[0185] The manner was all the same as Example 1 with the exception
that the silicon wafer was immersed in pure water for 1 min,
immersed in 2-propanol (iPA) for 1 min and immersed in toluene for
1 min after being immersed in hydrofluoric acid aqueous solution at
the above-mentioned "(2) Cleaning of Silicon Wafer". As shown in
the evaluation result of Table 3, the contact angle after the
surface treatment was 78.degree. and therefore the water
repellency-providing effect was exhibited. Additionally, the
capillary force at the time where water was retained was 0.7
MN/m.sup.2 and therefore the capillary force was small.
Additionally, the contact angle after UV irradiation was smaller
than 10.degree., so that removal of the water repellency-provided
surface condition was achieved. Furthermore, the Ra value of the
wafer after UV irradiation was smaller than 0.5 nm, with which it
was confirmed that the wafer was not eroded at the time of cleaning
and that the residue of the water-repellent cleaning liquid did not
remain after UV irradiation.
Example 27
[0186] The manner was all the same as Example 7 with the exception
that the silicon wafer was immersed in pure water for 1 min,
immersed in 2-propanol (iPA) for 1 min and immersed in
hydrofluoroether (HFE-7100 produced by 3M Limited) for 1 min after
being immersed in hydrofluoric acid aqueous solution at the
above-mentioned "(2) Cleaning of Silicon Wafer". As shown in the
evaluation result of Table 3, the contact angle after the surface
treatment was 78.degree. and therefore the water
repellency-providing effect was exhibited. Additionally, the
capillary force at the time where water was retained was 0.7
MN/m.sup.2 and therefore the capillary force was small.
Additionally, the contact angle after UV irradiation was smaller
than 10.degree., so that removal of the water repellency-provided
surface condition was achieved. Furthermore, the Ra value of the
wafer after UV irradiation was smaller than 0.5 nm, with which it
was confirmed that the wafer was not eroded at the time of cleaning
and that the residue of the water-repellent cleaning liquid did not
remain after UV irradiation.
Example 28
[0187] The manner was all the same as Example 1 with the exception
that the silicon wafer was immersed in pure water after being
immersed in hydrofluoric acid aqueous solution at the
above-mentioned "(2) Cleaning of Silicon Wafer". As shown in the
evaluation result of Table 3, the contact angle after the surface
treatment was 78.degree. and therefore the water
repellency-providing effect was exhibited. Additionally, the
capillary force at the time where water was retained was 0.7
MN/m.sup.2 and therefore the capillary force was small.
Additionally, the contact angle after UV irradiation was smaller
than 10.degree., so that removal of the water repellency-provided
surface condition was achieved. Furthermore, the Ra value of the
wafer after UV irradiation was smaller than 0.5 nm, with which it
was confirmed that the wafer was not eroded at the time of cleaning
and that the residue of the water-repellent cleaning liquid did not
remain after UV irradiation.
Example 29
[0188] The manner was all the same as Example 28 with the exception
that HFE-7100 was used as the organic solvent which is other than
the nitrogen-containing and contained in the water-repellent
cleaning liquid. As shown in the evaluation result of Table 3, the
contact angle after the surface treatment was 78.degree. and
therefore the water repellency-providing effect was exhibited.
Additionally, the capillary force at the time where water was
retained was 0.7 MN/m.sup.2 and therefore the capillary force was
small. Additionally, the contact angle after UV irradiation was
smaller than 10.degree., so that removal of the water
repellency-provided surface condition was achieved. Furthermore,
the Ra value of the wafer after UV irradiation was smaller than 0.5
nm, with which it was confirmed that the wafer was not eroded at
the time of cleaning and that the residue of the water-repellent
cleaning liquid did not remain after UV irradiation.
Example 30
[0189] The manner was all the same as Example 20 with the exception
that ethyldimethylchlorosilane [C.sub.2H.sub.5Si(CH.sub.3).sub.2Cl]
was used as the water-repellent compound. As shown in the
evaluation result of Table 3, the contact angle after the surface
treatment was 80.degree. and therefore the water
repellency-providing effect was excellently exhibited.
Additionally, the capillary force at the time where water was
retained was 0.6 MN/m.sup.2 and therefore the capillary force was
small. Additionally, the contact angle after UV irradiation was
smaller than 10.degree., so that removal of the water
repellency-provided surface condition was achieved. Furthermore,
the Ra value of the wafer after UV irradiation was smaller than 0.5
nm, with which it was confirmed that the wafer was not eroded at
the time of cleaning and that the residue of the water-repellent
cleaning liquid did not remain after UV irradiation.
Example 31
[0190] The manner was all the same as Example 20 with the exception
that propyldimethylchlorosilane
[C.sub.3H.sub.7Si(CH.sub.3).sub.2Cl] was used as the
water-repellent compound. As shown in the evaluation result of
Table 3, the contact angle after the surface treatment was
84.degree. and therefore the water repellency-providing effect was
excellently exhibited. Additionally, the capillary force at the
time where water was retained was 0.3 MN/m.sup.2 and therefore the
capillary force was small. Additionally, the contact angle after UV
irradiation was smaller than 10.degree., so that removal of the
water repellency-provided surface condition was achieved.
Furthermore, the Ra value of the wafer after UV irradiation was
smaller than 0.5 nm, with which it was confirmed that the wafer was
not eroded at the time of cleaning and that the residue of the
water-repellent cleaning liquid did not remain after UV
irradiation.
Comparative Example 1
[0191] The manner was the same as Example 1 with the exception that
the water-repellent cleaning liquid was not provided to the silicon
wafer. In other words, in this Comparative Example, a wafer which
is in a surface condition not provided with water repellency was
evaluated. As shown in the evaluation result of Table 3, the
contact angle of the wafer was 3.degree., i.e. small, while the
capillary force at the time where water was retained was 3.2
MN/m.sup.2, i.e. large.
Comparative Example 2
[0192] The manner was the same as Example 1 with the exception that
3.0 g of trimethylchlorosilane [(CH.sub.3).sub.3SiCl] was mixed
with 10.0 g of N,N-dimethylformamide (DMF) and 84.6 g of 2-propanol
(iPA), followed by adding 2.4 g of 0.1N nitric acid aqueous
solution (pH 1.0) and stirring at room temperature for about 24
hours thereby obtaining a water-repellent cleaning liquid. In other
words, in this Comparative Example, a water-repellent cleaning
liquid containing a water-repellent compound hydrolyzed at its
reactive moiety was used. As shown in the evaluation result of
Table 3, the contact angle after the surface treatment was
15.degree., i.e. small, while the capillary force at the time where
water was retained was 3.1 MN/m.sup.2, i.e. large.
EXPLANATION OF REFERENCE NUMERALS
[0193] 1 Silicon wafer [0194] 2 Finely uneven pattern that the
silicon wafer has at its surface [0195] 3 Projected portions of the
pattern [0196] 4 Recessed portions of the pattern [0197] 5 Width of
the recessed portions [0198] 6 Height of the projected portions
[0199] 7 Width of the projected portions [0200] 8 Cleaning liquid
retained in the recessed portions 4 [0201] 9 Water-based cleaning
liquid retained in the recessed portions 4 [0202] 10 Surface
condition provided with water repellency by a water-repellent
compound.
* * * * *